Annexin V binds to the actin-based cytoskeleton at the plasma membrane of activated platelets.
Immunocytochemical studies demonstrate that annexin V relocates to the plasma membranes of intact stimulated blood platelets. Anti-annexin V antibodies label the cytoplasmic side of the substrate-adherent plasma membrane of mechanically unroofed, glass-activated platelets and colocalize with actin. In addition, crosslinking experiments using detergent-solubilized membranes of activated platelets have identified an 85-kDa complex containing annexin V. The 85-kDa complex is also recognized by antibodies against actin, suggesting that annexin V interacts with actin. In addition, annexin V was found to associate with filamentous actin in the presence of millimolar Ca(2+). Annexin V was also shown by immunofluorescence microscopy to be associated with platelet cytoskeletons, colocalizing with actin in the presence of micromolar Ca(2+). These findings provide the first evidence for annexin V binding to the plasma membrane and to the actin-based cytoskeleton in activated platelets and indicate that annexin V may function in both cytoskeletal and membrane domains.
Tzima
E
E
School of Biochemistry and Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom.
Trotter
P J
PJ
Orchard
M A
MA
Walker
J H
JH
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D017304:Annexin A5 / Q000378:metabolism*; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D002118:Calcium / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D048429:Cell Size / Q000187:drug effects; D003432:Cross-Linking Reagents; D003572:Cytochalasins / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D004533:Egtazic Acid / Q000494:pharmacology; D005404:Fixatives; D005455:Fluorescent Antibody Technique; D005898:Glass; D006801:Humans; D008970:Molecular Weight; D015539:Platelet Activation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D011554:Pseudopodia / Q000187:drug effects
D000199:Actins; D017304:Annexin A5; D003432:Cross-Linking Reagents; D003572:Cytochalasins; D005404:Fixatives; C007215:cytochalasin E; D004533:Egtazic Acid; D002118:Calcium