J Biol Chem. 2011 Jul 1;286(26):22934-42. doi: 10.1074/jbc.M110.210930. Epub 2011 May 3.

Transient receptor potential mucolipin 1 (TRPML1) and two-pore channels are functionally independent organellar ion channels.External 2231691f894ba696de1310221b0a0dbbb31a7251e75115c265587c3d9d5f507c

Yamaguchi, S., Jha, A., Li, Q., Soyombo, A. A., Dickinson, G. D., Churamani, D., Brailoiu, E., Patel, S., Muallem, S.,
["Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75235, USA."]
NAADP is a potent second messenger that mobilizes Ca(2+) from acidic organelles such as endosomes and lysosomes. The molecular basis for Ca(2+) release by NAADP, however, is uncertain. TRP mucolipins (TRPMLs) and two-pore channels (TPCs) are Ca(2+)-permeable ion channels present within the endolysosomal system. Both have been proposed as targets for NAADP. In the present study, we probed possible physical and functional association of these ion channels. Exogenously expressed TRPML1 showed near complete colocalization with TPC2 and partial colocalization with TPC1. TRPML3 overlap with TPC2 was more modest. TRPML1 and to some extent TRPML3 co-immunoprecipitated with TPC2 but less so with TPC1. Current recording, however, showed that TPC1 and TPC2 did not affect the activity of wild-type TRPML1 or constitutively active TRPML1(V432P). N-terminally truncated TPC2 (TPC2delN), which is targeted to the plasma membrane, also failed to affect TRPML1 and TRPML1(V432P) channel function or TRPML1(V432P)-mediated Ca(2+) influx. Whereas overexpression of TPCs enhanced NAADP-mediated Ca(2+) signals, overexpression of TRPML1 did not, and the dominant negative TRPML1(D471K) was without affect on endogenous NAADP-mediated Ca(2+) signals. Furthermore, the single channel properties of NAADP-activated TPC2delN were not affected by TRPML1. Finally, NAADP-evoked Ca(2+) oscillations in pancreatic acinar cells were identical in wild-type and TRPML1(-/-) cells. We conclude that although TRPML1 and TPCs are present in the same complex, they function as two independent organellar ion channels and that TPCs, not TRPMLs, are the targets for NAADP.
PMID: 21540176External 2231691f894ba696de1310221b0a0dbbb31a7251e75115c265587c3d9d5f507c
Screening Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
  Experimental screening Non-experimental screening Reference
TRP channel construct Interactor source
TRP channel Interactor Method Species Region Species Organ/tissue Sample type
TRPML1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC1 Inference Prediction 21540176
TRPML1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC2 Inference Prediction 21540176
TRPML3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC1 Inference Prediction 21540176
TRPML3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC2 Inference Prediction 21540176
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
Validation: In vivo validation Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
  Assay with endogenous proteins Assay with overexpressed proteins Reference
Cell or tissue Cell or tissue TRP channel construct Interactor construct
TRP channel Interactor Method Species Region Species Region
TRPML1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC1 Co-immunofluorescence staining HEK293T Human Full-length Human Full-length 21540176
TRPML1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC1 Co-immunofluorescence staining HeLa Human Full-length Human Full-length 21540176
TRPML1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC1 Co-immunofluorescence staining SK-BR-3 Human Full-length Human Full-length 21540176
TRPML1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC1 Co-immunoprecipitation HEK293T Human Full-length Human Full-length 21540176
TRPML1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC2 Co-immunofluorescence staining HEK293T Human Full-length Human Full-length 21540176
TRPML1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC2 Co-immunofluorescence staining HeLa Human Full-length Human Full-length 21540176
TRPML1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC2 Co-immunofluorescence staining SK-BR-3 Human Full-length Human Full-length 21540176
TRPML1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC2 Co-immunoprecipitation HEK293T Human Full-length Human Full-length 21540176
TRPML3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC1 Co-immunofluorescence staining HEK293T Human Full-length Human Full-length 21540176
TRPML3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC1 Co-immunofluorescence staining HeLa Human Full-length Human Full-length 21540176
TRPML3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC1 Co-immunofluorescence staining SK-BR-3 Human Full-length Human Full-length 21540176
TRPML3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC1 Co-immunoprecipitation HEK293T Human Full-length Human Full-length 21540176
TRPML3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC2 Co-immunofluorescence staining HEK293T Human Full-length Human Full-length 21540176
TRPML3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC2 Co-immunofluorescence staining HeLa Human Full-length Human Full-length 21540176
TRPML3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC2 Co-immunofluorescence staining SK-BR-3 Human Full-length Human Full-length 21540176
TRPML3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TPC2 Co-immunoprecipitation HEK293T Human Full-length Human Full-length 21540176
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
TRP / Interactor

To prevent spam comments, we use reCAPTCHA. Please type correct words into the following box.