Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

This Article PDF (Full Text) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by LeBrasseur, N. Search for Related Content PubMed Articles by LeBrasseur, N. Social Bookmarking                      What's this?

Ca2+ increase (white) in injured cells is blocked by LDH-containing K+ATP channels (bottom). Jovanovic/Oxford

Achannel that protects cardiac cells from ischemia uses a rapid metabolite detection system to perceive dangerous conditions, according to new results from Russell Crawford, Aleksander Jovanovic, and colleagues (University of Dundee, Dundee, UK).

A heart attack damages cells when anaerobic conditions disrupt active ion transport, leading to a toxic increase in intracellular Ca²⁺. A decrease in ATP levels initially impairs ion transport, causing depolarization and Ca²⁺ import. However, low ATP may also trigger opening of ATP-sensitive K⁺ (K⁺_ATP) channels, which would counteract the depolarization, ultimately reducing the time for Ca²⁺ influx.

But ATP regulation is not the whole story, as K⁺_ATP channels open before intracellular ATP levels drop enough to open the channel. This prompted the group to search for additional components. They have now found that lactate dehydrogenase (LDH) interacts directly with the channel subunits. LDH catalyzes the reversible conversion of pyruvate to lactate, and thus may supply a local concentration of lactate to the channel. Indeed, the group demonstrated that lactate opened the channel despite high levels of ATP. Further, this regulated opening was crucial for the channel's ability to protect from ischemia.

Reference:

Crawford, R.M., et al. 2002. EMBO J. 21:3936–3948.[CrossRef][Medline]

Nicole LeBrasseur

lebrasn{at}rockefeller.edu

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This Article PDF (Full Text) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by LeBrasseur, N. Search for Related Content PubMed Articles by LeBrasseur, N. Social Bookmarking                      What's this?