Mary Wu

Macroautophagy is a mechanism employed by eukaryotic cells to recycle non-essential cellular components during starvation, differentiation, and development. Two conjugation reactions related to ubiquitination are essential for autophagy: Apg12p conjugation to Apg5p, and Apg8p conjugation to the lipid phosphatidylethanolamine. These reactions require the action of the E1-like enzyme, Apg7p, and the E2-like enzymes, Apg3p and Apg10p. InDictyostelium, development is induced by starvation, conditions under which autophagy is required for survival in yeast and plants. We have identified Dictyostelium homologues of 10 budding yeast autophagy genes. We have generated mutations inapg5 and apg7 that produce defects typically associated with an abrogation of autophagy. Mutants are not grossly affected in growth, but survival during nitrogen starvation is severely reduced. Starved mutant cells show little turnover of cellular constituents by electron microscopy, whereas wild-type cells show significant cytoplasmic degradation and reduced organelle number. Bulk protein degradation during starvation-induced development is reduced in the autophagy mutants. Development is aberrant; the autophagy mutants do not aggregate in plaques on bacterial lawns, but they do proceed further in development on nitrocellulose filters, forming defective fruiting bodies. The autophagy mutations are cell autonomous, because wild-type cells in a chimaera do not rescue development of the autophagy mutants. We have complemented the mutant phenotypes by expression of the cognate gene fused to green fluorescent protein. A green fluorescent protein fusion of the autophagosome marker Apg8 mislocalizes in the two autophagy mutants. We show that the Apg5-Apg12 conjugation system is conserved inDictyostelium. Macroautophagy is a mechanism employed by eukaryotic cells to recycle non-essential cellular components during starvation, differentiation, and development. Two conjugation reactions related to ubiquitination are essential for autophagy: Apg12p conjugation to Apg5p, and Apg8p conjugation to the lipid phosphatidylethanolamine. These reactions require the action of the E1-like enzyme, Apg7p, and the E2-like enzymes, Apg3p and Apg10p. InDictyostelium, development is induced by starvation, conditions under which autophagy is required for survival in yeast and plants. We have identified Dictyostelium homologues of 10 budding yeast autophagy genes. We have generated mutations inapg5 and apg7 that produce defects typically associated with an abrogation of autophagy. Mutants are not grossly affected in growth, but survival during nitrogen starvation is severely reduced. Starved mutant cells show little turnover of cellular constituents by electron microscopy, whereas wild-type cells show significant cytoplasmic degradation and reduced organelle number. Bulk protein degradation during starvation-induced development is reduced in the autophagy mutants. Development is aberrant; the autophagy mutants do not aggregate in plaques on bacterial lawns, but they do proceed further in development on nitrocellulose filters, forming defective fruiting bodies. The autophagy mutations are cell autonomous, because wild-type cells in a chimaera do not rescue development of the autophagy mutants. We have complemented the mutant phenotypes by expression of the cognate gene fused to green fluorescent protein. A green fluorescent protein fusion of the autophagosome marker Apg8 mislocalizes in the two autophagy mutants. We show that the Apg5-Apg12 conjugation system is conserved inDictyostelium. target of rapamycin green fluorescent protein Sorensen C Protein turnover in eukaryotes is accomplished by two major mechanisms, autophagy or proteasomal degradation. Three modes of autophagy have been identified: chaperone-mediated autophagy, microautophagy, and macroautophagy. In chaperone-mediated autophagy, specific proteins containing targeting sequences are bound by chaperones that mediate direct transport across the lysosomal membrane (1Dice J.F. Terlecky S.R. Chiang H.L. Olson T.S. Isenman L.D. Short-Russell S.R. Freundlieb S. Terlecky L.J. Semin. Cell Biol. 1990; 1: 449-455PubMed Google Scholar). A lysosomal receptor, lysosomal-associated membrane protein type 2a, interacts with the substrate to facilitate transport into the lysosome (2Cuervo A.M. Dice J.F. Traffic. 2000; 1: 570-583Crossref PubMed Scopus (221) Google Scholar, 3Cuervo A.M. Dice J.F. J. Cell Sci. 2000; 113: 4441-4450Crossref PubMed Google Scholar). Microautophagy is required for basal protein degradation in rat liver (4Mortimore G.E. Lardeux B.R. Adams C.E. J. Biol. Chem. 1988; 263: 2506-2512Abstract Full Text PDF PubMed Google Scholar) or glucose-induced peroxisome degradation in the methylotropic yeast Pichia pastoris (5Tuttle D.L. Dunn Jr., W.A. J. Cell Sci. 1995; 108: 25-35Crossref PubMed Google Scholar) and involves vacuolar membrane invagination to capture cargo directly. Macroautophagy is a non-selective mechanism used to deliver cytoplasmic components, including entire organelles, to the lysosome or vacuole during starvation (reviewed in Ref. 6Reggiori F. Klionsky D.J. Eukaryot. Cell. 2002; 1: 11-21Crossref PubMed Scopus (466) Google Scholar). Initially, a membrane distinct from the vacuole/lysosome encloses a portion of cytoplasm to form a double-membraned vesicle called an autophagosome or autophagic vacuole. The autophagosome docks at and fuses with the vacuole/lysosome, releasing a single-membraned vesicle called an autophagic body, which is degraded by resident hydrolases. Molecular genetic analysis in the budding yeast, Saccharomyces cerevisiae, has identified many of the genes that are required for autophagy (7Tsukada M. Ohsumi Y. FEBS Lett. 1993; 333: 169-174Crossref PubMed Scopus (1377) Google Scholar, 8Thumm M. Egner R. Koch B. Schlumpberger M. Straub M. Veenhuis M. Wolf D.H. FEBS Lett. 1994; 349: 275-280Crossref PubMed Scopus (479) Google Scholar, 9Noda T. Matsuura A. Wada Y. Ohsumi Y. Biochem. Biophys. Res. Commun. 1995; 210: 126-132Crossref PubMed Scopus (294) Google Scholar). These genes are required for phosphorylation reactions (10Noda T. Ohsumi Y. J. Biol. Chem. 1998; 273: 3963-3966Abstract Full Text Full Text PDF PubMed Scopus (1029) Google Scholar), a phosphatidylinositol 3-kinase complex (11Kametaka S. Okano T. Ohsumi M. Ohsumi Y. J. Biol. Chem. 1998; 273: 22284-22291Abstract Full Text Full Text PDF PubMed Scopus (216) Google Scholar, 12Kihara A. Noda T. Ishihara N. Ohsumi Y. J. Cell Biol. 2001; 152: 519-530Crossref PubMed Scopus (797) Google Scholar), and two novel ubiquitin-like conjugation reactions (13Mizushima N. Noda T. Yoshimori T. Tanaka Y. Ishii T. George M.D. Klionsky D.J. Ohsumi M. Ohsumi Y. Nature. 1998; 395: 395-398Crossref PubMed Scopus (1263) Google Scholar, 14Ichimura Y. Kirisako T. Takao T. Satomi Y. Shimonishi Y. Ishihara N. Mizushima N. Tanida I. Kominami E. Ohsumi M. Noda T. Ohsumi Y. Nature. 2000; 408: 488-492Crossref PubMed Scopus (1479) Google Scholar). Starvation releases the repression of autophagy by the target of rapamycin (Tor)1 protein kinase, leading to the activation of another serine/threonine kinase, Apg1p, which activates autophagy through unknown downstream targets (15Kamada Y. Funakoshi T. Shintani T. Nagano K. Ohsumi M. Ohsumi Y. J. Cell Biol. 2000; 150: 1507-1513Crossref PubMed Scopus (898) Google Scholar). Apg1p kinase activity is regulated by the phosphorylation status of a binding partner, Apg13; hyperphosphorylated Apg13p associates weakly with Apg1p. Upon Tor inactivation, Apg13p is dephosphorylated and binds more tightly to and activates Apg1p.Autophagosome formation also requires the activity of two protein conjugation systems mechanistically related to ubiquitination. In the first, the carboxyl-terminal glycine of Apg12p is conjugated to an internal lysine of Apg5p, through the action of E1-like and E2-like enzymes, Apg7p and Apg10p, respectively (16Shintani T. Mizushima N. Ogawa Y. Matsuura A. Noda T. Ohsumi Y. EMBO J. 1999; 18: 5234-5241Crossref PubMed Scopus (234) Google Scholar, 17Tanida I. Mizushima N. Kiyooka M. Ohsumi M. Ueno T. Ohsumi Y. Kominami E. Mol. Biol. Cell. 1999; 10: 1367-1379Crossref PubMed Scopus (324) Google Scholar, 18Yuan W. Stromhaug P.E. Dunn Jr., W.A. Mol. Biol. Cell. 1999; 10: 1353-1366Crossref PubMed Scopus (116) Google Scholar). Apg16p binds to Apg5p and then oligomerizes to produce Apg12p-Apg5p·Apg16p oligomers (19Kuma A. Mizushima N. Ishihara N. Ohsumi Y. J. Biol. Chem. 2002; 277: 18619-18625Abstract Full Text Full Text PDF PubMed Scopus (340) Google Scholar, 20Mizushima N. Noda T. Ohsumi Y. EMBO J. 1999; 18: 3888-3896Crossref PubMed Scopus (338) Google Scholar). A second conjugation system involves the conjugation of Apg8p/Aut7p to the membrane lipid phosphatidylethanolamine (14Ichimura Y. Kirisako T. Takao T. Satomi Y. Shimonishi Y. Ishihara N. Mizushima N. Tanida I. Kominami E. Ohsumi M. Noda T. Ohsumi Y. Nature. 2000; 408: 488-492Crossref PubMed Scopus (1479) Google Scholar, 21Kirisako T. Ichimura Y. Okada H. Kabeya Y. Mizushima N. Yoshimori T. Ohsumi M. Takao T. Noda T. Ohsumi Y. J. Cell Biol. 2000; 151: 263-276Crossref PubMed Scopus (724) Google Scholar), through the action of the E1-like and E2-like enzymes, Apg7p and Apg3p/Aut1p, respectively (22Schlumpberger M. Schaeffeler E. Straub M. Bredschneider M. Wolf D.H. Thumm M. J. Bacteriol. 1997; PubMed Scopus Google Scholar). Apg8p/Aut7p is the of the autophagy in yeast that is starvation T. M. Ishihara N. K. Ohsumi M. Yoshimori T. Noda T. Ohsumi Y. J. Cell Biol. 1999; PubMed Scopus Google is a that on but starvation a complex to produce a (reviewed in Ref. Cell and the Development of Google Scholar). aggregate a to form of The to produce a fruiting of a of a cellular development and a fruiting to to We that autophagy for Dictyostelium development. genetic that Dictyostelium is a to the on autophagy in budding yeast, and cells and to the of autophagy during development. We that apg7 are essential for Mutants in genes do not aggregate on of the wild-type but aggregate on nitrocellulose or The autophagy mutants have defects but of Protein which is induced by starvation, is reduced and of and are in two in and to and conjugated conjugation reactions to in budding We also the of a fusion of Apg8 and show the of autophagy on the of cells during show that the autophagy in yeast, and cells is conserved in We identified of S. proteins for and We to of or because they do not in are conserved in or because an A. a of protein with the of We the expression of of the identified autophagy genes and and cells are In yeast, the expression of autophagy is induced by starvation T. M. Ishihara N. K. Ohsumi M. Yoshimori T. Noda T. Ohsumi Y. J. Cell Biol. 1999; PubMed Scopus Google the of generated and the autophagy mutants in in the and apg7 genes. is the target of the activity of the E1-like enzyme, conjugation is to ubiquitination and is required for the formation of (13Mizushima N. Noda T. Yoshimori T. Tanaka Y. Ishii T. George M.D. Klionsky D.J. Ohsumi M. Ohsumi Y. Nature. 1998; 395: 395-398Crossref PubMed Scopus (1263) Google Scholar, N. H. Yoshimori T. Ohsumi Y. J. Biol. Chem. 1998; 273: Full Text Full Text PDF PubMed Scopus Google Scholar). Dictyostelium genes show significant with budding yeast, and with to essential for In the conjugation system to Two of the fusion proteins are in wild-type but the form of is in and the conjugated form of is in conjugation is with the to and from in budding yeast and and show cytoplasmic and a in and cells not The fusion a in on the status and genetic of the In the wild-type to many in the cytoplasm in to cytoplasmic the of the is in not and is in the and in These In the and a that is the in the wild-type and and the of not cells are is but with in that and apg7 are for in Dictyostelium but are required for development. mutants they form that to fruiting of and are These produce development and by autophagy mutant cells with wild-type cells in a autophagy mutations are cell is not mutations but with or and of autophagy mutants. in is severely reduced to that for yeast and plants. autophagy mutants of and autophagy mutations are to is the major mechanism of protein turnover yeast cells are for for of protein turnover (22Schlumpberger M. Schaeffeler E. Straub M. Bredschneider M. Wolf D.H. Thumm M. J. Bacteriol. 1997; PubMed Scopus Google Scholar). We that Dictyostelium autophagy mutants little protein whereas wild-type cells and complemented autophagy mutants of the protein they at the of A in a gene that is required for the to development S. A. 1998; Google Scholar), not the in protein of that the in development are not required for the of We a starvation-induced protein turnover is in an mutant not mutant also wild-type for not that autophagy induced in the of that are by with the protein turnover and by electron that turnover of and cytoplasmic constituents in cells for for is cells show significant degradation of the to an that of the cytoplasm are are that a of membrane and that in the mutant containing membrane and cytoplasm with little of degradation are These membrane are of or autophagic in cells T. Cell Res. PubMed Scopus Google Scholar, A. A. J. 2000; PubMed Scopus Google Scholar). The of the autophagic system more to cells to budding yeast and the more complex membrane and of Dictyostelium with In the the autophagosome fuses with the releasing the autophagic into the vacuolar for degradation by resident hydrolases. In in to to autophagic through of lysosomal membrane vacuole and of lysosomal Jr., W.A. J. Cell Biol. 1990; PubMed Scopus Google Scholar). electron are under to the of autophagy and the specific in the autophagy used to is conserved yeast, and and cell in yeast have the required for autophagy. The for the is to the required to autophagy, the of autophagosome and the of autophagy and Dictyostelium a system for is the system is to the of autophagy on development Protein turnover in eukaryotes is accomplished by two major mechanisms, autophagy or proteasomal degradation. Three modes of autophagy have been identified: chaperone-mediated autophagy, microautophagy, and macroautophagy. In chaperone-mediated autophagy, specific proteins containing targeting sequences are bound by chaperones that mediate direct transport across the lysosomal membrane (1Dice J.F. Terlecky S.R. Chiang H.L. Olson T.S. Isenman L.D. Short-Russell S.R. Freundlieb S. Terlecky L.J. Semin. Cell Biol. 1990; 1: 449-455PubMed Google Scholar). A lysosomal receptor, lysosomal-associated membrane protein type 2a, interacts with the substrate to facilitate transport into the lysosome (2Cuervo A.M. Dice J.F. Traffic. 2000; 1: 570-583Crossref PubMed Scopus (221) Google Scholar, 3Cuervo A.M. Dice J.F. J. Cell Sci. 2000; 113: 4441-4450Crossref PubMed Google Scholar). Microautophagy is required for basal protein degradation in rat liver (4Mortimore G.E. Lardeux B.R. Adams C.E. J. Biol. Chem. 1988; 263: 2506-2512Abstract Full Text PDF PubMed Google Scholar) or glucose-induced peroxisome degradation in the methylotropic yeast Pichia pastoris (5Tuttle D.L. Dunn Jr., W.A. J. Cell Sci. 1995; 108: 25-35Crossref PubMed Google Scholar) and involves vacuolar membrane invagination to capture cargo directly. Macroautophagy is a non-selective mechanism used to deliver cytoplasmic components, including entire organelles, to the lysosome or vacuole during starvation (reviewed in Ref. 6Reggiori F. Klionsky D.J. Eukaryot. Cell. 2002; 1: 11-21Crossref PubMed Scopus (466) Google Scholar). Initially, a membrane distinct from the vacuole/lysosome encloses a portion of cytoplasm to form a double-membraned vesicle called an autophagosome or autophagic vacuole. The autophagosome docks at and fuses with the vacuole/lysosome, releasing a single-membraned vesicle called an autophagic body, which is degraded by resident hydrolases. Molecular genetic analysis in the budding yeast, Saccharomyces cerevisiae, has identified many of the genes that are required for autophagy (7Tsukada M. Ohsumi Y. FEBS Lett. 1993; 333: 169-174Crossref PubMed Scopus (1377) Google Scholar, 8Thumm M. Egner R. Koch B. Schlumpberger M. Straub M. Veenhuis M. Wolf D.H. FEBS Lett. 1994; 349: 275-280Crossref PubMed Scopus (479) Google Scholar, 9Noda T. Matsuura A. Wada Y. Ohsumi Y. Biochem. Biophys. Res. Commun. 1995; 210: 126-132Crossref PubMed Scopus (294) Google Scholar). These genes are required for phosphorylation reactions (10Noda T. Ohsumi Y. J. Biol. Chem. 1998; 273: 3963-3966Abstract Full Text Full Text PDF PubMed Scopus (1029) Google Scholar), a phosphatidylinositol 3-kinase complex (11Kametaka S. Okano T. Ohsumi M. Ohsumi Y. J. Biol. Chem. 1998; 273: 22284-22291Abstract Full Text Full Text PDF PubMed Scopus (216) Google Scholar, 12Kihara A. Noda T. Ishihara N. Ohsumi Y. J. Cell Biol. 2001; 152: 519-530Crossref PubMed Scopus (797) Google Scholar), and two novel ubiquitin-like conjugation reactions (13Mizushima N. Noda T. Yoshimori T. Tanaka Y. Ishii T. George M.D. Klionsky D.J. Ohsumi M. Ohsumi Y. Nature. 1998; 395: 395-398Crossref PubMed Scopus (1263) Google Scholar, 14Ichimura Y. Kirisako T. Takao T. Satomi Y. Shimonishi Y. Ishihara N. Mizushima N. Tanida I. Kominami E. Ohsumi M. Noda T. Ohsumi Y. Nature. 2000; 408: 488-492Crossref PubMed Scopus (1479) Google Scholar). Starvation releases the repression of autophagy by the target of rapamycin (Tor)1 protein kinase, leading to the activation of another serine/threonine kinase, Apg1p, which activates autophagy through unknown downstream targets (15Kamada Y. Funakoshi T. Shintani T. Nagano K. Ohsumi M. Ohsumi Y. J. Cell Biol. 2000; 150: 1507-1513Crossref PubMed Scopus (898) Google Scholar). Apg1p kinase activity is regulated by the phosphorylation status of a binding partner, Apg13; hyperphosphorylated Apg13p associates weakly with Apg1p. Upon Tor inactivation, Apg13p is dephosphorylated and binds more tightly to and activates Apg1p. formation also requires the activity of two protein conjugation systems mechanistically related to ubiquitination. In the first, the carboxyl-terminal glycine of Apg12p is conjugated to an internal lysine of Apg5p, through the action of E1-like and E2-like enzymes, Apg7p and Apg10p, respectively (16Shintani T. Mizushima N. Ogawa Y. Matsuura A. Noda T. Ohsumi Y. EMBO J. 1999; 18: 5234-5241Crossref PubMed Scopus (234) Google Scholar, 17Tanida I. Mizushima N. Kiyooka M. Ohsumi M. Ueno T. Ohsumi Y. Kominami E. Mol. Biol. Cell. 1999; 10: 1367-1379Crossref PubMed Scopus (324) Google Scholar, 18Yuan W. Stromhaug P.E. Dunn Jr., W.A. Mol. Biol. Cell. 1999; 10: 1353-1366Crossref PubMed Scopus (116) Google Scholar). Apg16p binds to Apg5p and then oligomerizes to produce Apg12p-Apg5p·Apg16p oligomers (19Kuma A. Mizushima N. Ishihara N. Ohsumi Y. J. Biol. Chem. 2002; 277: 18619-18625Abstract Full Text Full Text PDF PubMed Scopus (340) Google Scholar, 20Mizushima N. Noda T. Ohsumi Y. EMBO J. 1999; 18: 3888-3896Crossref PubMed Scopus (338) Google Scholar). A second conjugation system involves the conjugation of Apg8p/Aut7p to the membrane lipid phosphatidylethanolamine (14Ichimura Y. Kirisako T. Takao T. Satomi Y. Shimonishi Y. Ishihara N. Mizushima N. Tanida I. Kominami E. Ohsumi M. Noda T. Ohsumi Y. Nature. 2000; 408: 488-492Crossref PubMed Scopus (1479) Google Scholar, 21Kirisako T. Ichimura Y. Okada H. Kabeya Y. Mizushima N. Yoshimori T. Ohsumi M. Takao T. Noda T. Ohsumi Y. J. Cell Biol. 2000; 151: 263-276Crossref PubMed Scopus (724) Google Scholar), through the action of the E1-like and E2-like enzymes, Apg7p and Apg3p/Aut1p, respectively (22Schlumpberger M. Schaeffeler E. Straub M. Bredschneider M. Wolf D.H. Thumm M. J. Bacteriol. 1997; PubMed Scopus Google Scholar). Apg8p/Aut7p is the of the autophagy in yeast that is starvation T. M. Ishihara N. K. Ohsumi M. Yoshimori T. Noda T. Ohsumi Y. J. Cell Biol. 1999; PubMed Scopus Google Scholar). Dictyostelium is a that on but starvation a complex to produce a (reviewed in Ref. Cell and the Development of Google Scholar). aggregate a to form of The to produce a fruiting of a of a cellular development and a fruiting to to We that autophagy for Dictyostelium development. genetic that Dictyostelium is a to the on autophagy in budding yeast, and cells and to the of autophagy during development. We that apg7 are essential for Mutants in genes do not aggregate on of the wild-type but aggregate on nitrocellulose or The autophagy mutants have defects but of Protein which is induced by starvation, is reduced and of and are in two in and to and conjugated conjugation reactions to in budding We also the of a fusion of Apg8 and show the of autophagy on the of cells during show that the autophagy in yeast, and cells is conserved in We identified of S. proteins for and We to of or because they do not in are conserved in or because an A. a of protein with the of We the expression of of the identified autophagy genes and and cells are In yeast, the expression of autophagy is induced by starvation T. M. Ishihara N. K. Ohsumi M. Yoshimori T. Noda T. Ohsumi Y. J. Cell Biol. 1999; PubMed Scopus Google the of generated and the autophagy mutants in in the and apg7 genes. is the target of the activity of the E1-like enzyme, conjugation is to ubiquitination and is required for the formation of (13Mizushima N. Noda T. Yoshimori T. Tanaka Y. Ishii T. George M.D. Klionsky D.J. Ohsumi M. Ohsumi Y. Nature. 1998; 395: 395-398Crossref PubMed Scopus (1263) Google Scholar, N. H. Yoshimori T. Ohsumi Y. J. Biol. Chem. 1998; 273: Full Text Full Text PDF PubMed Scopus Google Scholar). Dictyostelium genes show significant with budding yeast, and with to essential for In the conjugation system to Two of the fusion proteins are in wild-type but the form of is in and the conjugated form of is in conjugation is with the to and from in budding yeast and and show cytoplasmic and a in and cells not The fusion a in on the status and genetic of the In the wild-type to many in the cytoplasm in to cytoplasmic the of the is in not and is in the and in These In the and a that is the in the wild-type and and the of not cells are is but with in that and apg7 are for in Dictyostelium but are required for development. mutants they form that to fruiting of and are These produce development and by autophagy mutant cells with wild-type cells in a autophagy mutations are cell is not mutations but with or and of autophagy mutants. in is severely reduced to that for yeast and plants. autophagy mutants of and autophagy mutations are to is the major mechanism of protein turnover yeast cells are for for of protein turnover (22Schlumpberger M. Schaeffeler E. Straub M. Bredschneider M. Wolf D.H. Thumm M. J. Bacteriol. 1997; PubMed Scopus Google Scholar). We that Dictyostelium autophagy mutants little protein whereas wild-type cells and complemented autophagy mutants of the protein they at the of A in a gene that is required for the to development S. A. 1998; Google Scholar), not the in protein of that the in development are not required for the of We a starvation-induced protein turnover is in an mutant not mutant also wild-type for not that autophagy induced in the of that are by with the protein turnover and by electron that turnover of and cytoplasmic constituents in cells for for is cells show significant degradation of the to an that of the cytoplasm are are that a of membrane and that in the mutant containing membrane and cytoplasm with little of degradation are These membrane are of or autophagic in cells T. Cell Res. PubMed Scopus Google Scholar, A. A. J. 2000; PubMed Scopus Google Scholar). The of the autophagic system more to cells to budding yeast and the more complex membrane and of Dictyostelium with In the the autophagosome fuses with the releasing the autophagic into the vacuolar for degradation by resident hydrolases. In in to to autophagic through of lysosomal membrane vacuole and of lysosomal Jr., W.A. J. Cell Biol. 1990; PubMed Scopus Google Scholar). electron are under to the of autophagy and the specific in the autophagy used to is conserved yeast, and and cell in yeast have the required for autophagy. The for the is to the required to autophagy, the of autophagosome and the of autophagy and Dictyostelium a system for is the system is to the of autophagy on development In show that the autophagy in yeast, and cells is conserved in We identified of S. proteins for and We to of or because they do not in are conserved in or because an A. a of protein with the of We the expression of of the identified autophagy genes and and cells are In yeast, the expression of autophagy is induced by starvation T. M. Ishihara N. K. Ohsumi M. Yoshimori T. Noda T. Ohsumi Y. J. Cell Biol. 1999; PubMed Scopus Google Scholar). the of generated and the autophagy mutants in in the and apg7 genes. is the target of the activity of the E1-like enzyme, conjugation is to ubiquitination and is required for the formation of (13Mizushima N. Noda T. Yoshimori T. Tanaka Y. Ishii T. George M.D. Klionsky D.J. Ohsumi M. Ohsumi Y. Nature. 1998; 395: 395-398Crossref PubMed Scopus (1263) Google Scholar, N. H. Yoshimori T. Ohsumi Y. J. Biol. Chem. 1998; 273: Full Text Full Text PDF PubMed Scopus Google Scholar). Dictyostelium genes show significant with budding yeast, and with to essential for In the conjugation system to Two of the fusion proteins are in wild-type but the form of is in and the conjugated form of is in conjugation is with the to and from in budding yeast and and show cytoplasmic and a in and cells not The fusion a in on the status and genetic of the In the wild-type to many in the cytoplasm in to cytoplasmic the of the is in not and is in the and in These In the and a that is the in the wild-type and and the of not cells are is but with in We that and apg7 are for in Dictyostelium but are required for development. mutants they form that to fruiting of and are These produce development and by autophagy mutant cells with wild-type cells in a autophagy mutations are cell is not mutations but with or The and of autophagy mutants. in is severely reduced to that for yeast and plants. autophagy mutants of and autophagy mutations are to is the major mechanism of protein turnover yeast cells are for for of protein turnover (22Schlumpberger M. Schaeffeler E. Straub M. Bredschneider M. Wolf D.H. Thumm M. J. Bacteriol. 1997; PubMed Scopus Google Scholar). We that Dictyostelium autophagy mutants little protein whereas wild-type cells and complemented autophagy mutants of the protein they at the of A in a gene that is required for the to development S. A. 1998; Google Scholar), not the in protein of that the in development are not required for the of We a starvation-induced protein turnover is in an mutant not mutant also wild-type for not that autophagy induced in the of that are by with the protein turnover and by electron that turnover of and cytoplasmic constituents in cells for for is cells show significant degradation of the to an that of the cytoplasm are are that a of membrane and that in the mutant containing membrane and cytoplasm with little of degradation are These membrane are of or autophagic in cells T. Cell Res. PubMed Scopus Google Scholar, A. A. J. 2000; PubMed Scopus Google Scholar). The of the autophagic system more to cells to budding yeast and the more complex membrane and of Dictyostelium with In the the autophagosome fuses with the releasing the autophagic into the vacuolar for degradation by resident hydrolases. In in to to autophagic through of lysosomal membrane vacuole and of lysosomal Jr., W.A. J. Cell Biol. 1990; PubMed Scopus Google Scholar). electron are under to the of autophagy and the specific in the autophagy mutants. The used to is conserved yeast, and and cell in yeast have the required for autophagy. The for the is to the required to autophagy, the of autophagosome and the of autophagy and Dictyostelium a system for is the system is to the of autophagy on development We of the and and for We and for with We are to the Dictyostelium for

CAPTURE (NCT03226886) is a prospective cohort study of COVID-19 immunity in patients with cancer. Here we evaluated 585 patients following administration of two doses of BNT162b2 or AZD1222 vaccines, administered 12 weeks apart. Seroconversion rates after two doses were 85% and 59% in patients with solid and hematological malignancies, respectively. A lower proportion of patients had detectable neutralizing antibody titers (NAbT) against SARS-CoV-2 variants of concern (VOCs) vs wildtype (WT). Patients with hematological malignancies were more likely to have undetectable NAbT and had lower median NAbT vs solid cancers against both WT and VOCs. In comparison with individuals without cancer, patients with haematological, but not solid, malignancies had reduced NAb responses. Seroconversion showed poor concordance with NAbT against VOCs. Prior SARS-CoV-2 infection boosted NAb response including against VOCs, and anti-CD20 treatment was associated with undetectable NAbT. Vaccine-induced T-cell responses were detected in 80% of patients, and were comparable between vaccines or cancer types. Our results have implications for the management of cancer patients during the ongoing COVID-19 pandemic.