The Two-pore channel (TPC) interactome unmasks isoform-specific roles for TPCs in endolysosomal morphology and cell pigmentation

Yaping Lin-Moshier, Michael V. Keebler, Robert Hooper, Michael J. Boulware, Xiaolong Liu, Dev Churamani, Mary E. Abood, Timothy F. Walseth, Eugen Brailoiu, Sandip Patel, Jonathan S. Marchant

Research output: Contribution to journalArticlepeer-review

69 Scopus citations

Abstract

The two-pore channels (TPC1 and TPC2) belong to an ancient family of intracellular ion channels expressed in the endolysosomal system. Little is known about how regulatory inputs converge to modulate TPC activity, and proposed activation mechanisms are controversial. Here, we compiled a proteomic characterization of the human TPC interactome, which revealed that TPCs complex with many proteins involved in Ca2+homeostasis, trafficking, and membrane organization. Among these interactors, TPCs were resolved to scaffold Rab GTPases and regulate endomembrane dynamics in an isoform-specific manner. TPC2, but not TPC1, caused a proliferation of endolysosomal structures, dysregulating intracellular trafficking, and cellular pigmentation. These outcomes required both TPC2 and Rab activity, as well as their interactivity, because TPC2 mutants that were inactive, or rerouted away from their endogenous expression locale, or deficient in Rab binding, failed to replicate these outcomes. Nicotinic acid adenine dinucleotide phosphate (NAADP)- evoked Ca2+release was also impaired using either a Rab binding-defective TPC2 mutant or a Rab inhibitor. These data suggest a fundamental role for the ancient TPC complex in trafficking that holds relevance for lysosomal proliferative scenarios observed in disease.

Original languageEnglish (US)
Pages (from-to)13087-13092
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume111
Issue number36
DOIs
StatePublished - 2014

Keywords

  • Casignaling
  • Lysosome
  • Xenopus

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