Susan L. Cranmer

Nature Communications 7: Article number: 12862 (2016); Published: 27 September 2016; Updated: 30 August 2017 In Supplementary Fig. 7 of this Article, graphs presenting 6-PFK kinetics in panel d were inadvertently duplicated from those in panel c. The correct version of Supplementary Fig. 7 appears below as Fig.

Journal Article An alternative to serum for cultivation of Plasmodium falciparum in vitro Get access Susan L. Cranmer, Susan L. Cranmer 1Department of Microbiology, Monash University, Clayton 3168, Victoria, Australia Search for other works by this author on: Oxford Academic PubMed Google Scholar Cathleen Magowan, Cathleen Magowan 2Life Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720, USA Search for other works by this author on: Oxford Academic PubMed Google Scholar Joy Liang, Joy Liang 2Life Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720, USA Search for other works by this author on: Oxford Academic PubMed Google Scholar Ross L. Coppel, Ross L. Coppel 1Department of Microbiology, Monash University, Clayton 3168, Victoria, Australia Search for other works by this author on: Oxford Academic PubMed Google Scholar Brian M. Cooke Brian M. Cooke ∗ 1Department of Microbiology, Monash University, Clayton 3168, Victoria, Australia ∗Address for correspondence: Dr B. M. Cooke, Department of Microbiology, Monash University, Clayton 3168, Victoria, Australia; phone +61 3 9905 4827, fax +61 3 9905 4811. brian.cooke@med.monash.edu.au Search for other works by this author on: Oxford Academic PubMed Google Scholar Transactions of The Royal Society of Tropical Medicine and Hygiene, Volume 91, Issue 3, May-June 1997, Pages 363–365, https://doi.org/10.1016/S0035-9203(97)90110-3 Published: 01 June 1997 Article history Received: 07 October 1996 Revision received: 11 November 1996 Accepted: 12 November 1996 Published: 01 June 1997

Merozoite surface proteins of Plasmodium falciparum play a critical role in the invasion of human erythrocytes by the malaria parasite. Here we describe the identification of a novel protein with a molecular mass of 40 kDa that is found on the merozoite surface of P. falciparum. We call this protein merozoite surface protein 4 (MSP-4). Evidence for the surface location of MSP-4 includes (i) a staining pattern that is consistent with merozoite surface location in indirect immunofluorescent studies of cultured parasites, (ii) localization of MSP-4 in the detergent phase in Triton X-114 partitioning studies, and (iii) nucleotide sequencing studies which predict the presence of an N-terminal signal sequence and a hydrophobic C-terminal sequence in the protein. Immunoprecipitation studies of biosynthetically labelled parasites with [3H] myristic acid indicated that MSP-4 is anchored on the merozoite surface by a glycosylphosphatidylinositol moiety. Of considerable interest is the presence of a single epidermal growth factor-like domain at the C terminus of the MSP-4 protein, making it the second protein with such a structure to be found on the merozoite surface.

Platelet adhesion to sites of vascular injury is initiated by the binding of the platelet glycoprotein (GP) Ib-V-IX complex to matrix-bound von Willebrand factor (vWf). This receptor-ligand interaction is characterized by a rapid on-off rate that enables efficient platelet tethering and rolling under conditions of rapid blood flow. We demonstrate here that platelets adhering to immobilized vWf under flow conditions undergo rapid morphological conversion from flat discs to spiny spheres during surface translocation. Studies of Glanzmann thrombasthenic platelets (lacking integrin alpha(IIb)beta(3)) and Chinese hamster ovary (CHO) cells transfected with GPIb/IX (CHO-Ib/IX) confirmed that vWf binding to GPIb/IX was sufficient to induce actin polymerization and cytoskeletal reorganization independent of integrin alpha(IIb)beta(3). vWf-induced cytoskeletal reorganization occurred independently of several well characterized signaling processes linked to platelet activation, including calcium influx, prostaglandin metabolism, protein tyrosine phosphorylation, activation of protein kinase C or phosphatidylinositol 3-kinase but was critically dependent on the mobilization of intracellular calcium. Studies of Oregon Green 488 1, 2-bis(o-amino-5-fluorophenoxy)ethane-N,N,N',N-tetraacetic acid tetraacetoxymethyl ester-loaded platelets and CHO-Ib/IX cells demonstrated that these cells mobilize intracellular calcium in a shear-dependent manner during surface translocation on vWf. Taken together, these studies suggest that the vWf-GPIb interaction stimulates actin polymerization and cytoskeletal reorganization in rolling platelets via a shear-sensitive signaling pathway linked to intracellular calcium mobilization.

This study investigates three aspects of the adhesive interaction operating between platelet glycoprotein Ib/IX and integrin alpha(IIb)beta(3). These include the following: 1) examining the sufficiency of GPIb/IX and integrin alpha(IIb)beta(3) to mediate irreversible cell adhesion on immobilized von Willebrand factor (vWf) under flow; 2) the ability of the vWf-GPIb interaction to induce integrin alpha(IIb)beta(3) activation independent of endogenous platelet stimuli; and 3) the identification of key second messengers linking the vWf-GPIb/IX interaction to integrin alpha(IIb)beta(3) activation. By using Chinese hamster ovary cells transfected with GPIb/IX and integrin alpha(IIb)beta(3), we demonstrate that these receptors are both necessary and sufficient to mediate irreversible cell adhesion under flow, wherein GPIb/IX mediates cell tethering and rolling on immobilized vWf, and integrin alpha(IIb)beta(3) mediates cell arrest. Moreover, we demonstrate direct signaling between GPIb/IX and integrin alpha(IIb)beta(3). Studies on human platelets demonstrated that vWf binding to GPIb/IX is able to induce integrin alpha(IIb)beta(3) activation independent of endogenous platelet stimuli under both static and physiological flow conditions (150-1800 s(-)(1)). Analysis of the key second messengers linking the vWf-GPIb interaction to integrin alpha(IIb)beta(3) activation demonstrated that the first step in the activation process involves calcium release from internal stores, whereas transmembrane calcium influx is a secondary event potentiating integrin alpha(IIb)beta(3) activation.