4TM-TRPM8 channels are new gatekeepers of the ER-mitochondria Ca 2+ transfer

Biochim Biophys Acta Mol Cell Res. 2018 Jul;1865(7):981-994. doi: 10.1016/j.bbamcr.2018.04.007. Epub 2018 Apr 18.

Abstract

Calcium (Ca2+) release from the endoplasmic reticulum plays an important role in many cell-fate defining cellular processes. Traditionally, this Ca2+ release was associated with the ER Ca2+ release channels, inositol 1,4,5‑triphosphate receptor (IP3R) and ryanodine receptor (RyR). Lately, however, other calcium conductances have been found to be intracellularly localized and to participate in cell fate regulation. Nonetheless, molecular identity and functional properties of the ER Ca2+ release mechanisms associated with multiple diseases, e.g. prostate cancer, remain unknown. Here we identify a new family of transient receptor potential melastatine 8 (TRPM8) channel isoforms as functional ER Ca2+ release channels expressed in mitochondria-associated ER membranes (MAMs). These TRPM8 isoforms exhibit an unconventional structure with 4 transmembrane domains (TMs) instead of 6 TMs characteristic of the TRP channel archetype. We show that these 4TM-TRPM8 isoforms form functional channels in the ER and participate in regulation of the steady-state Ca2+ concentration ([Ca2+]) in mitochondria and the ER. Thus, our study identifies 4TM-TRPM8 isoforms as ER Ca2+ release mechanism distinct from classical Ca2+ release channels.

Keywords: Alternate transcription; ER calcium fluxes; MAMs; Mitochondria; Prostate cancer; TRP channel.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Alternative Splicing
  • Calcium / metabolism*
  • Cell Line, Tumor
  • Endoplasmic Reticulum / metabolism*
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Male
  • Middle Aged
  • Mitochondria / metabolism*
  • Prostate / cytology
  • Prostate / metabolism
  • Prostatic Neoplasms / genetics
  • Prostatic Neoplasms / metabolism*
  • Protein Domains
  • TRPM Cation Channels / chemistry
  • TRPM Cation Channels / genetics*
  • TRPM Cation Channels / metabolism*

Substances

  • TRPM Cation Channels
  • TRPM8 protein, human
  • Calcium