Insulin-like growth factor-1 induces tyrosyl phosphorylation of nuclear proteins.

Abstract

Stimulation of mesangial cells with insulin-like growth factor-1 (IGF-1) resulted in the rapid tyrosyl phosphorylation of nuclear proteins as indicated by fluorescence microscopy of cells stained with anti-phosphotyrosine antibodies. Immunoprecipitation of nuclear extracts with anti-phosphotyrosine antibodies revealed that IGF-1 induced a transient increase in immunoreactive phosphotyrosine in nuclear proteins of 43, 95, and 160 kDa. Using a double immunoprecipitation protocol, the transcription factor c-Jun was also found to increase in immunoreactive phosphotyrosine in response to IGF-1. A similar pattern of tyrosyl phosphorylation of nuclear proteins was observed in the epidermoid carcinoma cell line CaSki. These data suggest that tyrosyl phosphorylation of nuclear proteins may be a step in the transduction of mitogenic signals.

• Authors: B S Oemar, N M Law, S A Rosenzweig
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 266 Issue 36 Pg. 24241-4 (Dec 25 1991) ISSN: 0021-9258 [Print] United States
• PMID: 1662205 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Nuclear Proteins
• Proto-Oncogene Proteins c-jun
• Receptors, Cell Surface
• Receptors, Somatomedin
• Tyrosine
• Insulin-Like Growth Factor I

Topics

• Animals
• Blotting, Western
• Cells, Cultured
• Electrophoresis, Polyacrylamide Gel
• Glomerular Mesangium (cytology, metabolism)
• Insulin-Like Growth Factor I (physiology)
• Mice
• Mice, Inbred C57BL
• Microscopy, Fluorescence
• Nuclear Proteins (metabolism)
• Phosphorylation
• Precipitin Tests
• Proto-Oncogene Proteins c-jun (metabolism)
• Receptors, Cell Surface (metabolism)
• Receptors, Somatomedin
• Signal Transduction
• Tyrosine (metabolism)