Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2000 Jun 2;275(22):16530-5.
doi: 10.1074/jbc.C000090200.

Specific properties of T-type calcium channels generated by the human alpha 1I subunit

A Monteil  1 , J Chemin, V Leuranguer, C Altier, G Mennessier, E Bourinet, P Lory, J Nargeot
Affiliations
Free article

Specific properties of T-type calcium channels generated by the human alpha 1I subunit

A Monteil et al. J Biol Chem. .
Free article

Abstract

We have cloned and expressed a human alpha(1I) subunit that encodes a subtype of T-type calcium channels. The predicted protein is 95% homologous to its rat counterpart but has a distinct COOH-terminal region. Its mRNA is detected almost exclusively in the human brain, as well as in adrenal and thyroid glands. Calcium currents generated by the functional expression of human alpha(1I) and alpha(1G) subunits in HEK-293 cells were compared. The alpha(1I) current activated and inactivated approximately 10 mV more positively. Activation and inactivation kinetics were up to six times slower, while deactivation kinetics was faster and showed little voltage dependence. A slower recovery from inactivation, a lower sensitivity to Ni(2+) ions (IC(50) approximately 180 micrometer), and a larger channel conductance (approximately 11 picosiemens) were the other discriminative features of the alpha(1I) current. These data demonstrate that the alpha(1I) subunit encodes T-type Ca(2+) channels functionally distinct from those generated by the human alpha(1G) or alpha(1H) subunits and point out that human and rat alpha(1I) subunits have species-specific properties not only in their primary sequence, but also in their expression profile and electrophysiological behavior.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

Publication types

Substances

Associated data