Open AccessInhibitory Effect of Annexin V on Protein Kinase C Activity in Mesangial Cell Lysates
Author(s) -
Rothhut Bernard,
Dubois Thierry,
Feliers Denis,
RussoMarie Françoise,
Oudinet JeanPaul
Publication year - 1995
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1995.0865a.x
Subject(s) - protein kinase c , annexin a2 , annexin , annexin a1 , phosphorylation , phosphatidylserine , microbiology and biotechnology , kinase , signal transduction , protein kinase a , calcium binding protein , biology , biochemistry , chemistry , calcium , in vitro , phospholipid , organic chemistry , membrane
Annexin V belongs to a large family of calcium‐binding and phospholipid‐binding proteins and may act as an endogenous regulator of the protein kinase C (PKC) activity. This study examines the effect of annexin V on the in vitro PKC activity in cultured mesangial cells using histone H1, the peptide [Ser25]PKC‐(19–31), or endogenous proteins as substrates. The SDS/PAGE pattern of 32 P‐labeled mesangial proteins showed that the calcium‐independent PKC [(n+a)PKC] phosphorylated several proteins from 70 kDa to 40 kDa and 22 kDa to 15 kDa. Three additional proteins from 34 kDa to 29 kDa, including annexin I and its proteolytic forms, were detected after activation of calcium‐dependent PKC (cPKC). Increasing concentrations of annexin V did not alter the phosphorylation of (n+a)PKC substrates. By contrast, specific phosphorylation of proteins and annexin I by cPKC, was reduced in a dose‐dependent manner. Addition of high concentration of calcium and phosphatidylserine did not reverse the inhibitory effect of annexin V. Annexin V also inhibited the phosphorylation of histone H1 or peptide [Ser25]PKC‐(19–31) by cPKC. Moreover, removal of annexin V from cytosols increased the annexin I phosphorylation by these isoforms. From these results, we propose that annexin V may regulate the signal‐transduction pathway involving the activation of cPKC, as they act in vitro as an inhibitor of these kinases.