Luminal chloride-dependent activation of endosome calcium channels: Patch clamp study of enlarged endosomes

Mitsuyoshi Saito, Phyllis I. Hanson, Paul Schlesinger

Research output: Contribution to journalArticlepeer-review

72 Scopus citations

Abstract

Although Ca2+ release from early endosomes (EE) is important for the fusion of primary endosomes, the presence of an ion channel responsible for releasing calcium from the EE has not been shown. A recent proteomics study has identified the TRPV2 channel protein in EE, suggesting that transient receptor potential-like Ca2+ channels may be in endosomes. The submicron size of endosomes has made it difficult to study their ion channels in the past. We have overcome this problem by generating enlarged EE with the help of a hydrolysis-deficient SKD1/VPS4B mutant in HEK293 cells. Here we report the first patch clamp recording of a novel endosome calcium channel (ECC) in these enlarged EE. The ECC shows a similar pharmacology to that of the TRPV2 channel. In addition, the ECC has a unique chloride-dependent regulation; it is inhibited by the endosome luminal chloride with a K50 of 82 mM.

Original languageEnglish
Pages (from-to)27327-27333
Number of pages7
JournalJournal of Biological Chemistry
Volume282
Issue number37
DOIs
StatePublished - Sep 14 2007

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