TDAG51 mediates the effects of insulin-like growth factor I (IGF-I) on cell survival

Yuka Toyoshima, Michael Karas, Shoshana Yakar, Joelle Dupont, Lee Helman, Derek LeRoith

Research output: Contribution to journalArticlepeer-review


Insulin-like growth factor-I (IGF-I) receptors and insulin receptors belong to the same subfamily of receptor tyrosine kinases and share a similar set of intracellular signaling pathways, despite their distinct biological actions. In the present study, we evaluated T cell death-associated gene 51 (TDAG51), which we previously identified by cDNA microarray analysis as a gene specifically induced by IGF-I. We characterized the signaling pathways by which IGF-I induces TDAG51 gene expression and the functional role of TDAG51 in IGF-I signaling in NIH-3T3 (NWTb3) cells, which overexpress the human IGF-I receptor. Treatment with IGF-I increased TDAG51 mRNA and protein levels in NWTb3 cells. This effect of IGF-I was specifically mediated by the IGF-IR, because IGF-I did not induce TDAG51 expression in NIH-3T3 cells overexpressing a dominant-negative IGF-I receptor. Through the use of specific inhibitors of various protein kinases, we found that IGF-I induced TDAG51 expression via the p38 MAPK pathway. The ERK, JNK, and phosphatidylinositol 3-kinase pathways were not involved in IGF-I-induced regulation of TDAG51. To assess the role of TDAG51 in IGF-I signaling, we used small interfering RNA (siRNA) expression vectors directed at two different target sites to reduce the level of TDAG51 protein. In cells expressing these siRNA vectors, TDAG51 protein levels were decreased by 75-80%. Furthermore, TDAG51 siRNA expression abolished the ability of IGF-I to rescue cells from serum starvation-induced apoptosis. These findings suggest that TDAG51 plays an important role in the anti-apoptotic effects of IGF-I.

Original languageEnglish (US)
Pages (from-to)25898-25904
Number of pages7
JournalJournal of Biological Chemistry
Issue number24
StatePublished - Jun 11 2004

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


Dive into the research topics of 'TDAG51 mediates the effects of insulin-like growth factor I (IGF-I) on cell survival'. Together they form a unique fingerprint.

Cite this