Endocrinology, Vol 137, 4358-4362, Copyright © 1996 by Endocrine Society

ARTICLES

Growth hormone induces tyrosine phosphorylation of annexin I in rat osteosarcoma cells

JP Salles, JC Netelenbos and MC Slootweg
Research Institute for Endocrinology, Reproduction, and Metabolism, Free University Hospital, Amsterdam, The Netherlands.

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.

This article has been cited by other articles:

				C. Ohlsson, B.-A. Bengtsson, O. G. P. Isaksson, T. T. Andreassen, and M. C. Slootweg Growth Hormone and Bone Endocr. Rev., February 1, 1998; 19(1): 55 - 79. [Abstract] [Full Text]