Referenced in: none

Automatically associated channels: Cav3.1

Title: Phosphatidylinositol-3 phosphatase myotubularin-related protein 6 negatively regulates CD4 T cells.

Authors: Shekhar Srivastava, Kyung Ko, Papiya Choudhury, Zhai Li, Amanda K Johnson, Vivek Nadkarni, Derya Unutmaz, William A Coetzee, Edward Y Skolnik

Journal, date & volume: Mol. Cell. Biol., 2006 Aug , 26, 5595-602

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/16847315

Abstract
Intracellular Ca2+ levels rapidly rise following cross-linking of the T-cell receptor (TCR) and function as a critical intracellular second messenger in T-cell activation. It has been relatively under appreciated that K+ channels play an important role in Ca2+ influx into T lymphocytes by helping to maintain a negative membrane potential which provides an electrochemical gradient to drive Ca2+ influx. Here we show that the Ca2+-activated K+ channel, KCa3.1, which is critical for Ca2+ influx in reactivated naive T cells and central memory T cells, requires phosphatidylinositol-3 phosphatase [PI(3)P] for activation and is inhibited by the PI(3)P phosphatase myotubularin-related protein 6 (MTMR6). Moreover, by inhibiting KCa3.1, MTMR6 functions as a negative regulator of Ca2+ influx and proliferation of reactivated human CD4 T cells. These findings point to a new and unexpected role for PI(3)P and the PI(3)P phosphatase MTMR6 in the regulation of Ca2+ influx in activated CD4 T cells and suggest that MTMR6 plays a critical role in setting a minimum threshold for a stimulus to activate a T cell.