Radhakrishnan K, Kamp MA, Siapich SA, Hescheler J, Lüke M, Schneider T. Ca(v)2.3 Ca2+ channel interacts with the G1-subunit of V-ATPase.
Cell Physiol Biochem 2011;
27:421-32. [PMID:
21691059 DOI:
10.1159/000329963]
[Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/05/2011] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND
Calcium channels are essential in coupling action potential to signal transduction in cells. There are several types of calcium channels, which can be pharmacologically classified as L-, N-, P/Q-, R- and T-type. But molecular basis of R-type channels is less clearly understood compared the other channel types. Therefore the current study aims at understanding the molecular functions of R-type calcium channels by identifying interaction partners of the channel.
METHODS
In order to do so, a yeast two hybrid (Y2H) screen, with carboxy terminus of α1 subunit of the channel, as the bait, was performed. G1 subunit of v-ATPase was identified as a putative interaction partner of human Ca(v)2.3 by using the Y2H screening. The interaction was confirmed by immunoprecipitation. To study the functional importance of the interaction, bafilomycin A(1), a potent and specific inhibitor of v-ATPase was used in patch-clamp recordings in Ca(v)2.3 stably-transfected HEK-293 cells (2C6) as well as in electroretinography of the isolated bovine retina expressing R-type Ca(2+) channels.
RESULTS
G1 subunit of v-ATPase interacts with C-terminal tail of Ca(v)2.3 and bafilomycin A(1) reduces Ca(v)2.3 mediated calcium currents. Additionally peak I(Ca) is inhibited in retinal signal transduction when recorded as ERG b-wave.
CONCLUSIONS
The results suggest that v-ATPase interacts physically and also functionally with Ca(v)2.3. This is the first demonstration of association of Ca(v)2.3 C-terminus with a protein complex which is involved in transmembrane signalling.
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