Faculty Collaboration Database

Rho small GTPases activate the epithelial Na(+) channel. J Biol Chem 2004 Nov 26;279(48):49989-94

Date

09/28/2004

Pubmed ID

15448132

DOI

10.1074/jbc.M409812200

Scopus ID

2-s2.0-9644307893 (requires institutional sign-in at Scopus site)   65 Citations

Abstract

Small G proteins in the Rho family are known to regulate diverse cellular processes, including cytoskeletal organization and cell cycling, and more recently, ion channel activity and activity of phosphatidylinositol 4-phosphate 5-kinase (PI(4)P 5-K). The present study investigates regulation of the epithelial Na(+) channel (ENaC) by Rho GTPases. We demonstrate here that RhoA and Rac1 markedly increase ENaC activity. Activation by RhoA was suppressed by the C3 exoenzyme. Inhibition of the downstream RhoA effector Rho kinase, which is necessary for RhoA activation of PI(4)P 5-K, abolished ENaC activation. Similar to RhoA, overexpression of PI(4)P 5-K increased ENaC activity suggesting that production of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) in response to RhoA-Rho kinase signaling stimulates ENaC. Supporting this idea, inhibition of phosphatidylinositol 4-kinase, but not the RhoA effector phosphatidylinositol 3-kinase and MAPK cascades, markedly attenuated RhoA-dependent activation of ENaC. RhoA increased ENaC activity by increasing the plasma membrane levels of this channel. We conclude that RhoA activates ENaC via Rho kinase and subsequently activates PI(4)P 5-K with concomitant increases in PI(4,5)P(2) levels promoting channel insertion into the plasma membrane.

Author List

Staruschenko A, Nichols A, Medina JL, Camacho P, Zheleznova NN, Stockand JD

MESH terms used to index this publication - Major topics in bold

Animals
COS Cells
Cell Membrane
Phosphotransferases (Alcohol Group Acceptor)
Sodium Channels
rho GTP-Binding Proteins