Premium
Enhancement by ganglioside GT1b of annexin I phosphorylation in bovine mammary gland in the presence of phosphatidylserine and Ca 2+
Author(s) -
Katoh Norio,
Miyamoto Toru
Publication year - 1996
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02522693
Subject(s) - phosphorylation , protein kinase c , annexin , phosphatidylserine , microbiology and biotechnology , protein kinase a , biochemistry , kinase , protein phosphorylation , ganglioside , biology , chemistry , phospholipid , flow cytometry , membrane
Ganglioside GT1b and, to a lesser extent, GD3, enhanced phosphorylation of a 36 kDa protein (the substrate of protein kinase C) in the particulate fraction from bovine mammary gland. Sialic acids, asialogangliosides, and GM3 were without effect, and GD1a conversely inhibited phosphorylation of the 36 kDa protein. The enhanced phosphorylation by GT1b required the simultaneous presence of phosphatidylserine (PS) and Ca 2+ . The 36 kDa protein reacted with anti‐annexin I in Western blot analysis. Addition of purified annexin I to the reaction mixture containing the particulate fraction increased the extent of phosphorylated 36 kDa protein, and the phosphorylation was further enhanced by GT1b. The enhanced phosphorylation of annexin I by GT1b was also dependent on PS and Ca 2+ . When annexin I was phosphorylated by purified protein kinase C, GT1b inhibited the annexin I phosphorylation. Addition of epidermal growth factor or insulin to the particulate fraction had little effect on the enhancement. These results suggest that an enzyme or enzymes other than protein kinase C, epidermal growth factor receptor kinase, or insulin receptor kinase is responsible for the GT1b‐ and GD3‐enhanced phosphorylation of annexin I in the presence of PS and Ca 2+ .