Cell Biology

An Intersectin between Endocytosis and Signal Transduction

Science's STKE  05 Sep 2000:
Vol. 2000, Issue 48, pp. tw7
DOI: 10.1126/stke.2000.48.tw7

Intersectins are a family of adaptor proteins involved in endocytosis. Evidence is mounting for signal transduction that is tightly coupled to endocytosis. Adams et al. show that Xenopus intersectin with two epsin15 homology (EH) domains and five SH3 domains can activate Elk-1-mediated transcription in transfected cells. Furthermore, this activation is enhanced if just the EH domains are expressed and is suppressed if the SH3 domains are expressed, suggesting that the EH domains are the activating region and that the SH3 domain acts to negatively regulate this activity. Transfection of intersection potentiated epidermal growth factor (EGF)-stimulated Elk-1 signaling. Although EGF signaling to Elk-1 was inhibited by a chemical that blocks mitogen-activated and extracellular signal-regulated protein kinases 1 and 2, signaling by intersectin was not, indicating that intersectin activates Elk-1 through a separate signal transduction cascade. Further support for a role for intersectin in signal transduction came from its ability to transform rodent fibroblasts and its ability to enhance the rate of oocyte maturation in the presence of progesterone when expressed in Xenopus oocytes.

Adams, A., Thorn, J.M., Yamabhai, M., Kay, B.K., and O'Bryan, J.P. (2000) Intersectin, an adaptor protein involved in clathrin-mediated endocytosis, activates mitogenic signaling pathways. J. Biol. Chem. 275: 27414-27420. [Abstract] [Full Text]