Modulation of annexin II tetramer by tyrosine phosphorylation

Abstract

Annexin II tetramer (AIIt) is a Ca(2+)-dependent phospholipid-binding phosphoprotein. In cells either expressing transforming protein tyrosine kinases or treated with growth factors such as PDGF, AIIt has been shown to contain increased levels of phosphotyrosine. Therefore, we have examined the effects of the in vitro phosphorylation of AIIt by pp60c-src on several activities of the protein. AIIt was phosphorylated by pp60c-src to 0.91 +/- 0.07 mol of phosphate/mol of AIIt (mean +/- SD). The protein tyrosine phosphorylation of AIIt completely inhibited the ability of the protein to bind to and bundle F-actin. In contrast, the phosphoprotein and native protein bound to purified adrenal medulla chromaffin granules with similar affinity; however, the chromaffin granule bridging activity of the phosphoprotein was abolished. The inhibition of the chromaffin granule bridging activity of the phosphoprotein could be partially reversed by the addition of millimolar Ca2+. Furthermore, the phosphorylation of AIIt by pp60c-src inhibited the in vitro ability of this annexin to form a complex consisting of plasma membrane, chromaffin granules, and AIIt. In addition to binding to biological membranes, some annexin proteins have been shown to possess carbohydrate-binding activity. Although native AIIt bound to a heparin affinity column, tyrosine phosphorylation of AIIt blocked the ability of the protein to bind to the heparin affinity column. These results suggest that the tyrosine phosphorylation of AIIt is a negative modulator of AIIt and that the dephosphorylation of AIIt might be necessary for activation of the protein.

Fusion of Lamellar Body with Plasma Membrane Is Driven by the Dual Action of Annexin II Tetramer and Arachidonic Acid

“…However, precise mechanisms of AIIt-mediated fusion of plasma membrane and lamellar body in this exocytotic process are far from fully elucidated. The majority of the evidence for a role of AIIt in membrane fusion is based on model membrane (13,15,16,22). In this study we established a sensitive in vitro assay for the fusion of lamellar bodies with the plasma membrane using a fluorescent probe R18, and we demonstrated a critical role of AIIt and arachidonic acid in this process.…”

“…Serine or tyrosine residues near the N terminus of annexin II can be phosphorylated by protein kinase C and tyrosine kinase pp60 c-Src , respectively. In vitro phosphorylation of these sites reduces the ability of this protein to aggregate vesicles without affecting its membrane binding capacity (21,22). We have shown recently (23,24) that the modification of cysteine or tyrosine residues of annexin II by nitric oxide or peroxynitrite leads to the loss of its liposome aggregation activity.…”

“…Other groups also used liposomes to mimic granule membrane or plasma membrane (10,15,16,21,22,25). However, a direct biochemical analysis of the ability of AIIt to fuse plasma membrane with lamellar bodies or other granule membranes has not been reported.…”

2D-DIGE analysis of phospho-enriched fractions from dasatinib-treated melanoma cell lines

“…SRC kinase can directly phosphorylate ANXA2 on Y23 [26,27], which may negatively modulate ANXA2 function and inhibit the ability of ANXA2 to bind F-actin [27]. However, another study showed that phosphorylation of ANXA2 Y23 is essential for ANXA2 function and its association with the endosome [19].…”

“…The ANXA2-S100A10 complex has a channel modulating effect on the cell surface which can affect the membrane interactions of lipids [29]. SRC kinase has been shown to phosphorlyate both ANXA2 [26,27] and S100A10 [30].…”