TRIM4 interacts with TRPM8 and regulates its channel function through K423-mediated ubiquitination

Area of Science:

• Molecular Biology
• Cell Physiology
• Ion Channel Function

Background:

• Transient receptor potential melastatin member 8 (TRPM8) is a cold-activated cation channel involved in pain signaling (allodynia).
• TRPM8 dysfunction and abnormal expression are implicated in human cancers.
• The regulatory mechanisms of TRPM8, particularly ubiquitination, are not well understood.

Purpose of the Study:

• To investigate the role of ubiquitination in regulating TRPM8 channel function.
• To identify novel interaction partners of TRPM8 involved in its ubiquitination and regulation.
• To elucidate the specific molecular mechanisms by which TRIM4 affects TRPM8.

Main Methods:

• Co-immunoprecipitation to identify TRIM4 as a TRPM8 interaction partner.
• Patch-clamp electrophysiology to assess TRPM8 channel activity.
• Western blotting and immunofluorescence to analyze TRPM8 expression and ubiquitination.
• Site-directed mutagenesis to identify the ubiquitination site.

Main Results:

• TRIM4 directly interacts with TRPM8 via its SPRY domain.
• TRIM4 negatively regulates TRPM8 currents and reduces cell surface expression.
• TRIM4 promotes K63-linked ubiquitination of TRPM8 at lysine residue 423.
• UBA1 (Ub-activating enzyme E1) interacts with TRPM8 and is required for TRIM4-mediated regulation.

Conclusions:

• TRIM4 acts as an E3 ubiquitin ligase that downregulates TRPM8 channel activity and surface expression.
• TRIM4-mediated TRPM8 regulation occurs through K423 ubiquitination and requires UBA1.
• This study reveals a novel ubiquitination-dependent pathway for TRPM8 regulation.