The Annexins and Exocytosis

Abstract

The annexins are a group of homologous proteins that bind phospholipids in the presence of calcium. They may provide a major pathway for communication between cellular membranes and their cytoplasmic environment. Annexins have a characteristic "bivalent" activity in the sense that they can draw two membranes together when activated by calcium. This has led to the hypothesis that certain members of this protein family may initiate contact and fusion between a secretory vesicle membrane and the plasma membrane during the process of exocytosis.

Cholesterol transport from late endosomes to the Golgi regulates t-SNARE trafficking, assembly, and function

“…The role of AnxA6 in secretion has not been extensively investigated, but in line with the data presented here, the available evidence suggests that AnxA6 inhibits rather than potentiates the secretory process (Creutz, 1992; Donnelly and Moss, 1997; Podszywalow-Bartnicka et al , 2010). We previously identified a significant diminution of vesicular stomatitis virus G protein transport (a well-characterized marker for constitutive transport through the secretory pathway) in CHO-A6 cells (Cubells et al , 2007).…”

Characterization of Phospholipase A2 Activity in Reticulocyte Endocytic Vesicles

“…PLA, involvement could facilitate membrane fusion by releasing fatty acids from phospholipids. Indeed, arachidonic acid, a cisunsaturated fatty acid, was demonstrated to promote membrane fusion in different systems (Creutz, 1992;Meers et al, 1988;Burger and Verkleij, 1990). There are also arguments indicating a role of a PLA, in exocytosis (Morgan and Burgoyne, 1992;Zupan et al, 1992).…”

A rise in nuclear calcium translocates annexins IV and V to the nuclear envelope

“…The annexins (Anxs) constitute a family of Ca2+-dependent phospholipid-binding proteins including 13 members with a similar structure, characterized by the presence of four or eight repeats of a 70-amino-acid segment and a variable Nterminal extremity (for recent reviews see [1][2][3]). A main property they share is their ability to bind to negatively charged phospholipids in the presence of Ca 2+, which appears to be responsible for their anti-phospholipase, anti-coagulant, antiinflammatory, and anti-protein kinase C activities, as well as their capacity to drive Ca2+-dependent aggregation of secretory granules.…”