Role of IRS-1 and SHC activation in 3T3-L1 fibroblasts differentiation

C. Laurino, R. Cordera

Research output: Contribution to journalArticlepeer-review


The early steps of 3T3-L1 fibroblasts differentiation to adipocytes are characterized by a proliferation phase, termed clonal expansion, that ends after the first 48 h of exposure of confluent cells to high doses of insulin, dexamethasone, 3-methyl-isobutylxanthine and FCS (differentiation mix). Since insulin is a key hormone for adipocyte conversion, and IRS-1 (insulin receptor substrate -1) and Shc (Src homology collagen) - proximal intracellular substrates of the insulin receptor - control cell proliferation, the aim of this study was to investigate the role of IRS-1 and Shc in the early steps of differentiation. At the end of clonal expansion, 48 h after induction of differentiation with differentiation mix, p66 Shc phosphorylation and IRS-1 amounts were reduced in those cells committed to fully differentiate. Conversely, in cells treated with insulin alone or dexamethasone alone (unable to be differentiated), p66 Shc and IRS-1 activities were maintained unaltered, compared to basal values. These observations suggest that the modifications of p66 Shc and IRS-1 in the first 48 h of 3T3-L1 conversion into adipocytes could play a role on this process, or alternatively they could represent an early cellular marker of differentiation.

Original languageEnglish
Pages (from-to)363-367
Number of pages5
JournalGrowth Hormone and IGF Research
Issue number5
Publication statusPublished - 1998

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism


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