Cell Biology

Tale of Two Two-Timing Proteins

Science's STKE  10 Oct 2006:
Vol. 2006, Issue 356, pp. tw345
DOI: 10.1126/stke.3562006tw345

Cells put many proteins to more than one use, including the transcription factor TFII-I. Caraveo et al. (see the Perspective by Park and Dolmetsch) found that TFII-I may inhibit calcium entry into cells by interacting with another protein that itself has dual roles in regulating cellular calcium concentrations--phospholipase C-γ (PLC-γ). PLC-γ promotes the generation of inositol 1,4,5-trisphosphate, a second messenger that causes calcium release from intracellular stores, and also interacts with the membrane calcium channel TRPC3 and promotes insertion of the channel into the plasma membrane. The interaction of TFII-I with PLC-γ appears to depend on TFII-I’s phosphorylation, which may keep PLC-γ from interacting with the TRPC3 channel and thereby limit calcium entry through the plasma membrane.

G. Caraveo, D. B. van Rossum, R. L. Patterson, S. H. Snyder, S. Desiderio, Action of TFII-I outside the nucleus as an inhibitor of agonist-induced calcium entry. Science 314, 122-125 (2006). [Abstract] [Full Text]

C. Y. Park, R. Dolmetsch, The double life of a transcription factor takes it outside the nucleus. Science 314, 64-65 (2006). [Abstract] [Full Text]