Referenced in: none

Automatically associated channels: Cav3.1 , Cav3.3

Title: Determinants of the differential gating properties of Cav3.1 and Cav3.3 T-type channels: a role of domain IV?

Authors: J Hamid, J B Peloquin, A Monteil, G W Zamponi

Journal, date & volume: Neuroscience, 2006 Dec , 143, 717-28

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/16996222

Abstract
We have investigated the channel structural determinants that underlie the difference in gating properties of Cav3.1 and Cav3.3 T-type channels, by creating a series of chimeric channel constructs in which the major transmembrane domains were swapped. The chimeras were then expressed in tsA-201 cells and subjected to whole cell patch clamp analysis. Our data reveal that domains I and IV are major determinants of the half-activation potential. Substitution of domain IV was the most important determinant of activation time constant and time constant for recovery from inactivation, with domains I and II mediating a smaller role. In contrast, the carboxy terminal region did not appear to be involved. Determinants of the time constant for inactivation could not be localized to a specific transmembrane domain, but the concomitant substitution of domains I+IV was able to partially confer the inactivation kinetics among the two wild type channels. Our data indicate that the domain IV region mediates an important role in T-type channel activation, whereas multiple channel structural determinants appear to control T-type channel inactivation.