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Control of late G0/G1 progression and protein modification by SmC/IGF I

Control of late G0/G1 progression and protein modification by SmC/IGF I

Authors :
N. E. Olashaw
W. J. Pledger
J. J. Van Wyk
Source :
American Journal of Physiology-Cell Physiology. 253:C575-C579
Publication Year :
1987
Publisher :
American Physiological Society, 1987.

Abstract

Somatomedin C/insulin-like growth factor I (SmC/IGF I) mediates traverse of late G0/G1 in density-arrested BALB/c-3T3 cells from a distinct growth arrest point in mid-G0/G1 (the V point) to the initiation of DNA synthesis. As a prelude to future studies aimed at defining the mechanism of action of SmC/IGF I, we investigated the level (e.g., transcriptional, translational) at which SmC/IGF I modulates V to S traverse. The post-V point progression of cells arrested at the V point by amino acid starvation and released into amino acid-replenished medium containing SmC/IGF I, insulin, or platelet-poor plasma (PPP) did not require either mRNA synthesis or an increase in the overall level of protein synthesis. Although two-dimensional gel analysis of proteins prepared from SmC/IGF I-treated cells did not reveal any preferentially synthesized proteins, several SmC/IGF I-induced protein modifications, which result in an increase in isoelectric point (pI) and occur in the absence of mRNA synthesis, were evident. These findings suggest that SmC/IGF I modulates late G0/G1 progression by a posttranscriptional process that may involve protein modification.

Details

ISSN :
15221563 and 03636143
Volume :
253
Database :
OpenAIRE
Journal :
American Journal of Physiology-Cell Physiology
Accession number :
edsair.doi.dedup.....1683b29b6d128c4355d0cd586f97c001
Full Text :
https://doi.org/10.1152/ajpcell.1987.253.4.c575