TY - JOUR
T1 - Luminal chloride-dependent activation of endosome calcium channels
T2 - Patch clamp study of enlarged endosomes
AU - Saito, Mitsuyoshi
AU - Hanson, Phyllis I.
AU - Schlesinger, Paul
PY - 2007/9/14
Y1 - 2007/9/14
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=34848916433&partnerID=8YFLogxK
U2 - 10.1074/jbc.M702557200
DO - 10.1074/jbc.M702557200
M3 - Article
C2 - 17609211
AN - SCOPUS:34848916433
SN - 0021-9258
VL - 282
SP - 27327
EP - 27333
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 37
ER -