The molecular appearance of native TRPM7 channel complexes identified by high-resolution proteomics

Elife. 2021 Nov 12;10:e68544. doi: 10.7554/eLife.68544.

Abstract

The transient receptor potential melastatin-subfamily member 7 (TRPM7) is a ubiquitously expressed membrane protein consisting of ion channel and protein kinase domains. TRPM7 plays a fundamental role in the cellular uptake of divalent cations such as Zn2+, Mg2+, and Ca2+, and thus shapes cellular excitability, plasticity, and metabolic activity. The molecular appearance and operation of TRPM7 channels in native tissues have remained unresolved. Here, we investigated the subunit composition of endogenous TRPM7 channels in rodent brain by multi-epitope affinity purification and high-resolution quantitative mass spectrometry (MS) analysis. We found that native TRPM7 channels are high-molecular-weight multi-protein complexes that contain the putative metal transporter proteins CNNM1-4 and a small G-protein ADP-ribosylation factor-like protein 15 (ARL15). Heterologous reconstitution experiments confirmed the formation of TRPM7/CNNM/ARL15 ternary complexes and indicated that complex formation effectively and specifically impacts TRPM7 activity. These results open up new avenues towards a mechanistic understanding of the cellular regulation and function of TRPM7 channels.

Keywords: TRPM7 complexes; Xenopus; biochemistry; brain; chemical biology; human; mouse; proteome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / metabolism*
  • Female
  • HEK293 Cells
  • Humans
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Proteomics / methods*
  • Rats
  • Rats, Wistar
  • TRPM Cation Channels / genetics*
  • TRPM Cation Channels / metabolism

Substances

  • TRPM Cation Channels
  • Trpm7 protein, mouse
  • Trpm7 protein, rat

Grant support

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.