Thrombin stimulates the intracellular relocation of annexin V in human platelets

Relocation of annexin V to platelet membranes is a phosphorylation-dependent process

“…In addition, subcellular fractionation studies have shown that in heart, lung, liver, platelets and brain a proportion of the total annexin V remains associated with membranes even after extraction with EGTA. It is therefore likely that annexin V plays a role in the regulation of a membranelocalized process [7,8,[25][26][27][28]. We have demonstrated that, following physiological platelet activation, annexin V relocates from the cytosol and binds to membranes, which implicates annexin V in coupling increases in cytosolic [Ca# + ] to membranespecific processes [7,8].…”

“…When platelets are stimulated with 0.1 unit\ml thrombin or 5 µM A23187 in the presence of 1 mM extracellular Ca# + , annexin V binds to the membranes in a manner that cannot be reversed by EGTA extraction (Figure 1 ; [7,8]). In order to investigate…”

“…It is therefore likely that annexin V plays a role in the regulation of a membranelocalized process [7,8,[25][26][27][28]. We have demonstrated that, following physiological platelet activation, annexin V relocates from the cytosol and binds to membranes, which implicates annexin V in coupling increases in cytosolic [Ca# + ] to membranespecific processes [7,8]. Subsequent studies have shown that annexin V also relocates to membranes following increases in intracellular calcium in the human osteosarcoma cell line MG-63…”

“…Annexins are a family of at least thirteen proteins that contain repeats of a highly conserved 70-amino-acid sequence [2][3][4][5][6]. Annexin V is the most ubiquitous annexin and has been reported to be present in almost all mammalian cells, including blood platelets [7][8][9][10][11][12]. Although the exact physiological function of annexin V remains unclear, it has been implicated in ion-channel regulation [13][14][15][16], as an inhibitor of protein kinase C [17][18][19][20][21], as an inhibitor of blood coagulation [22,23] and as an inhibitor of phospholipase A # [24].…”

Two Novel Intrinsic Annexins Accumulate in Wheat Membranes in Response to Low Temperature

“…They are usually considered as soluble calcium dependent phospholipid binding proteins but recent reports have suggested that they could also be tightly associated with cellular membranes (Sheets et al 1987, Valentine-Braun et al 1987, Campos-Gonzales et al 1989, Pula et al 1990, Bianchi et al 1992, Boustead et al 1993, Futter et al 1993, Tagoe et al 1994, Bohm et al 1994, Trotter et al 1994, Blanchard et al 1996, Liu et al 1997, Harder et al 1997, Jost et al 1997, Turpin et al 1998. Annexins have a common structure consisting of a core domain of four or eight repeated sequences containing calcium and phospholipid binding sites.…”