Growth hormone induces tyrosine phosphorylation of annexin I in rat osteosarcoma cells.
GH induces phosphorylation of a number of cellular proteins, of which several have now been identified, such as mitogen-activated protein kinase, insulin receptor substrate-1, and members of the JAK kinase and STAT families of proteins. However, other phosphorylated proteins remain unidentified. Growth factors and cytokines, including epidermal growth factor, insulin, pp60v-scr, and angiotensin II, induce a rapid phosphorylation of annexin I, a 35-kDa member of the annexin family of Ca2+ and phospholipid-binding proteins. The osteoblast-like rat osteosarcoma cell-line UMR-106.01, in which GH acts as a mitogen via a high affinity GH receptor, was used as a model for GH-induced protein phosphorylation. It is demonstrated by immunoblotting and immunoprecipitation techniques that GH induces the phosphorylation of annexin I on tyrosine residues. This phosphorylation is dose and time dependent. Induction of annexin I phosphorylation is delayed compared with that of JAK2. These results identify annexin I as a protein that becomes tyrosine phosphorylated under the influence of GH and show that phosphorylation of annexin I is a general phenomenon that follows activation of a cell by hormones or cytokines.
Salles
J P
JP
Research Institute for Endocrinology, Reproduction, and Metabolism, Free University Hospital, Amsterdam, The Netherlands.
Netelenbos
J C
JC
Slootweg
M C
MC
D000818:Animals; D017305:Annexin A1 / Q000378:metabolism*; D019382:Human Growth Hormone / Q000494:pharmacology*; D006801:Humans; D012516:Osteosarcoma / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D051381:Rats; D011994:Recombinant Proteins; D013997:Time Factors; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism*
D017305:Annexin A1; D011994:Recombinant Proteins; D019382:Human Growth Hormone; D014443:Tyrosine