Dexamethasone Induces Rapid Serine-Phosphorylation and Membrane Translocation of Annexin 1 in a Human Folliculostellate Cell Line via a Novel Nongenomic Mechanism Involving the Glucocorticoid Receptor, Protein Kinase C, Phosphatidylinositol 3-Kinase, and Mitogen-Activated Protein Kinase

Abstract

Our recent studies on rat pituitary tissue suggest that the annexin 1 (ANXA1)-dependent inhibitory actions of glucocorticoids on ACTH secretion are effected via a paracrine mechanism that involves protein kinase C (PKC)-dependent translocation of a serine-phosphorylated species of ANXA1 (Ser-P-ANXA1) to the plasma membrane of the nonsecretory folliculostellate cells. In the present study, we have used a human folliculostellate cell line (PDFS) to explore the signaling mechanisms that cause the translocation of Ser-P-ANXA1 to the membrane together with Western blot analysis and flow cytometry to detect the phosphorylated protein. Exposure of PDFS cells to dexamethasone caused time-dependent increases in the expression of ANXA1 mRNA and protein, which were first detected within 2 h of steroid contact. This genomic response was preceded by the appearance within 30 min of substantially increased amounts of Ser-P-ANXA1 and by translocation of the phosphorylated protein to the cell surface. The prompt membrane translocation of Ser-P-ANXA1 provoked by dexamethasone was inhibited by the glucocorticoid receptor, antagonist, mifepristone, but not by actinomycin D or cycloheximide, which effectively inhibit mRNA and protein synthesis respectively in our preparation. It was also inhibited by a nonselective PKC inhibitor (PKC(9-31)), by a selective inhibitor of Ca(2+)-dependent PKCs (Go 6976) and by annexin 5 (which sequesters PKC in other systems). In addition, blockade of phosphatidylinositiol 3-kinase (wortmannin) or MAPK pathways with PD 98059 or UO 126 (selective for MAPK kinse 1 and 2) prevented the steroid-induced translocation of Ser-P-ANXA1 to the cell surface. These results suggest that glucocorticoids induce rapid serine phosphorylation and membrane translocation of ANXA1 via a novel nongenomic, glucocorticoid receptor-dependent mechanism that requires MAPK, phosphatidylinositiol 3-kinase, and Ca(2+)-dependent PKC pathways.

Multiple signaling pathways involved in stimulation of osteoblast differentiation by N-methyl-D-aspartate receptors activation in vitro

“…It is a substrate for protein kinase C and protein tyrosine kinases and has multiple phosphorylation sites as well as calcium and phospholipid binding properties [29] . Anxa1 was also shown to be activated as a consequence of sequential PI3K-PKC activation [30,31] . Matrix metalloproteinases (MMPs) are a family of secreted or transmembrane zinc-dependent endopeptidases.…”

Prognostic Significance of Annexin A1 Expression in Pancreatic Ductal Adenocarcinoma

“…For instance, at intracellular level, annexin A1 can interact with the cytosolic form of phospholipase A2 (cPLA2) and cyclooxygenase 2 (COX-2) to block enzyme activity (Kim et al, 1994;Hannon et al, 2003), and annexin A1 can mediate apoptosis by inducing the dephosphorylation of BAD, allowing BAD to translocate to the mitochondria, whereas annexin A1 itself translocates to the nucleus (Solito et al, 2003a), however, the mechanism and functional relevance of annexin A1 nuclear localization is still unknown, and annexin A1 also can be phosphorylated by EGF-R tyrosine kinase, protein kinase C (PKC), platelet-derived growth factor receptor tyrosine kinase (PDGFR-TK), and hepatocyte growth factor receptor tyrosine kinase (HGFR-TK) to mediate proliferation (Lim & Pervaiz., 2007); at the external membrane level, annexin A1 acts as a negative regulator of inflammatory process, including blocking the rolling of polymorphonuclear leukocyte on endothelial cells (Perretti et al, 1996), and also acts on its receptor, identified as the fomyl peptide receptor (FPR) and the formyl peptide receptor like-1 (FPRL1), to inhibit cell adhesion and migration, as well as inducing detachment of adherent cells (Rescher et al, 2002). Moreover, it can be phosphorylated and translocated to membrane by glucocorticosteroid through PKC (protein kinase C), PI3K, MAP kinase (mitogen activated protein kinase) and Ca2+ dependent pathways (Solito et al, 2003b), and binds to phosphatidylserine to mediate the engulfment of apoptotic cells when recruited to the cell surface (Arur et al, 2003).…”

Annexin 1: a paracrine/juxtacrine mediator of glucorticoid action in the neuroendocrine system

“…17 Our recent studies have shown that the glucocorticoid-induced exportation of annexin 1 from pituitary tissue is blocked by PKC inhibitors, as too is the steroid-induced inhibition of ACTH secretion, and that the exported protein is serine-phosphorylated. 12,18 Studies using green fluorescence protein (GFP)-linked annexin 1 constructs suggest that serine-27 is particularly important in this regard as tagged proteins in which this site is mutated to alanine are not transported to the cell surface. 19 Further studies have shown that the initial steroid-induced exportation of the native protein is effected via a novel, GCreceptor mediated, non-genomic signalling mechanism involving PI3-kinase, MAP-kinase and PKC.…”

“…19 Further studies have shown that the initial steroid-induced exportation of the native protein is effected via a novel, GCreceptor mediated, non-genomic signalling mechanism involving PI3-kinase, MAP-kinase and PKC. 18 In addition, they have provided functional and histological evidence that the translocation of the protein across the plasma membrane is effected via a member of the ATP binding cassette family of proteins (ABC A1 20 ). In particular, confocal imaging has demonstrated co-localization of annexin 1 and the ABC A1 annexin 1 and neuroendocrine function 219 transport protein at junctions of follicostellate cells and corticotrophs, suggesting that annexin 1 may subserve a juxtacrine role.…”