SNF8, a Member of the ESCRT-II Complex, Interacts With TRPC6 and Enhances Its Channel Activity

BMC Cell Biol. 2012 Nov 21;13:33. doi: 10.1186/1471-2121-13-33.

Abstract

Background: Transient receptor potential canonical (TRPC) channels are non-selective cation channels involved in receptor-mediated calcium signaling in diverse cells and tissues. The canonical transient receptor potential 6 (TRPC6) has been implicated in several pathological processes, including focal segmental glomerulosclerosis (FSGS), cardiac hypertrophy, and pulmonary hypertension. The two large cytoplasmic segments of the cation channel play a critical role in the proper regulation of channel activity, and are involved in several protein-protein interactions.

Results: Here we report that SNF8, a component of the endosomal sorting complex for transport-II (ESCRT-II) complex, interacts with TRPC6. The interaction was initially observed in a yeast two-hybrid screen using the amino-terminal cytoplasmic domain of TRPC6 as bait, and confirmed by co-immunoprecipitation from eukaryotic cell extracts. The amino-terminal 107 amino acids are necessary and sufficient for the interaction. Overexpression of SNF8 enhances both wild-type and gain-of-function mutant TRPC6-mediated whole-cell currents in HEK293T cells. Furthermore, activation of NFAT-mediated transcription by gain-of-function mutants is enhanced by overexpression of SNF8, and partially inhibited by RNAi mediated knockdown of SNF8. Although the ESCRT-II complex functions in the endocytosis and lysosomal degradation of transmembrane proteins, SNF8 overexpression does not alter the amount of TRPC6 present on the cell surface.

Conclusion: SNF8 is novel binding partner of TRPC6, binding to the amino-terminal cytoplasmic domain of the channel. Modulating SNF8 expression levels alters the TRPC6 channel current and can modulate activation of NFAT-mediated transcription downstream of gain-of-function mutant TRPC6. Taken together, these results identify SNF8 as a novel regulator of TRPC6.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Endosomal Sorting Complexes Required for Transport / antagonists & inhibitors
  • Endosomal Sorting Complexes Required for Transport / genetics
  • Endosomal Sorting Complexes Required for Transport / metabolism*
  • HEK293 Cells
  • Humans
  • Immunoprecipitation
  • Mutation
  • NFATC Transcription Factors / metabolism
  • Protein Binding
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Signal Transduction
  • TRPC Cation Channels / genetics
  • TRPC Cation Channels / metabolism*
  • TRPC6 Cation Channel
  • Transcription, Genetic
  • Two-Hybrid System Techniques

Substances

  • Endosomal Sorting Complexes Required for Transport
  • NFATC Transcription Factors
  • RNA, Small Interfering
  • SNF8 protein, human
  • TRPC Cation Channels
  • TRPC6 Cation Channel
  • TRPC6 protein, human