Jump to: Page Content, Section Navigation, Site Navigation, Site Search, Account Information, or Site Tools.
Guest Alerts | Access Rights | My Account | Sign In
|
|
© 2000 by The American Society for Biochemistry and Molecular Biology, Inc.
J Biol Chem, Vol. 275, Issue 7, 4561-4564, February 18, 2000 Plasma Membrane Calcium Channels in Human Carcinoma A431 Cells Are Functionally Coupled to Inositol 1,4,5-Trisphosphate Receptor-Phosphatidylinositol 4,5-Bisphosphate Complexes* , , , , ¶
From the In most nonexcitable cells, calcium
(Ca2+) release from inositol 1,4,5-trisphosphate
(InsP3)-sensitive intracellular Ca2+ stores is
coupled to Ca2+ influx (calcium release-activated
channels (ICRAC)) pathway. Despite
intense investigation, the molecular identity of
ICRAC and the mechanism of its activation
remain poorly understood. InsP3-dependent
miniature calcium channels (Imin) display
functional properties characteristic for ICRAC.
Here we used patch clamp recordings of Imin
channels in human carcinoma A431 cells to demonstrate that
Imin activity was greatly enchanced in the
presence of anti-phosphatidylinositol 4,5-bisphosphate antibody
(PIP2Ab) and diminished in the presence of
PIP2. Anti-PIP2 antibody induced a greater than
6-fold increase in Imin sensitivity for
InsP3 activation and an almost 4-fold change in
Imin maximal open probability. The addition of
exogenous PIP2 vesicles to the cytosolic surface of
inside-out patches inhibited Imin activity.
These results lead us to propose an existence of a Ca2+
influx pathway in nonexcitable cells activated via direct
conformational coupling with a selected population of InsP3
receptors, located just underneath the plasma membrane and coupled to
PIP2. The described pathway provides for a highly
compartmentalized Ca2+ influx and intracellular
Ca2+ store refilling mechanism.
* This work was supported by a grant from the Russian Basic Research Foundation (to G. N. M) and by National Institutes of Health Grant NS38082 (to I. B.).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. ¶ To whom correspondence should be addressed. Tel.: 812-247-1497; Fax: 812-247-0341; E-mail: gnmozh@link.cytspb.rssi.ru. Copyright © 2000 by The American Society for Biochemistry and Molecular Biology, Inc.
THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
|
Science Signaling. ISSN 1937-9145 (pre-2008: Science's STKE. ISSN 1525-8882)