TRPM

TRPM or Transient Receptor Potential Melastatin is a subfamily of Transient Receptor Potential (TRP) channels. TRPM channels are a large group of ion channels located primarily on the plasma membrane of numerous animal cell types. These channels are best known for their roles in sensory transduction, particularly in taste and temperature sensation.

Structure and Function

TRPM channels are composed of four subunits, each containing six transmembrane segments, a pore-forming loop between the fifth and sixth segments, and both the N- and C-termini located intracellularly. The N-terminus contains a TRP domain and multiple ankyrin repeats, while the C-terminus contains a coiled-coil domain and a TRP domain.

TRPM channels are non-selective cation channels that are usually permeable to both monovalent and divalent cations, including sodium, potassium, calcium, and magnesium ions. They are involved in a variety of physiological processes, including sensory perception, cell proliferation, and cell death.

Subtypes

There are eight known subtypes of TRPM channels, designated TRPM1 through TRPM8. Each subtype has unique properties and distribution patterns.

• TRPM1 is expressed in melanocytes and the retina, and mutations in this gene are associated with congenital stationary night blindness and melanoma.
• TRPM2 is expressed in many tissues and cells, and is involved in oxidative stress-induced cell death.
• TRPM3 is expressed in the brain, kidney, and cardiovascular system, and is involved in pain perception and insulin secretion.
• TRPM4 and TRPM5 are calcium-activated non-selective cation channels involved in taste transduction.
• TRPM6 and TRPM7 are unique among TRP channels in that they possess an additional kinase domain, and are involved in magnesium homeostasis.
• TRPM8 is expressed in sensory neurons and is involved in cold sensation.

Clinical Significance

Mutations in TRPM channels have been linked to a variety of diseases, including neurodegenerative disorders, cardiovascular diseases, and cancer. For example, mutations in TRPM1 are associated with melanoma and congenital stationary night blindness, while mutations in TRPM6 and TRPM7 are associated with hypomagnesemia.

Furthermore, TRPM channels are potential therapeutic targets for a variety of conditions, including pain, cancer, and cardiovascular diseases. For example, TRPM8 antagonists are being developed as potential treatments for pain and cancer.

See Also

• Transient Receptor Potential Channels
• Ion Channels
• Sensory Transduction

References

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