The protein encoded by this gene is a member of the transient receptor potential (TRP) family of non-selective cation channels. It is expressed in the retina, in a subset of bipolar cells termed ON bipolar cells.[4][5] These cells form synapses with either rods or cones, collecting signals from them. In the dark, the signal arrives in the form of the neurotransmitter glutamate, which is detected by a G protein-coupled receptor (GPCR) signal transduction cascade. Detection of glutamate by the GPCR Metabotropic glutamate receptor 6 results in closing of the TRPM1 channel. At the onset of light, glutamate release is halted and mGluR6 is deactivated; this results in opening of the TRPM1 channel, influx of sodium and calcium, and depolarization of the bipolar cell.[6][7]
In addition to the retina, TRPM1 is also expressed in melanocytes, which are melanin-producing cells in the skin. The expression of TRPM1 is inversely correlated with melanoma aggressiveness, suggesting that it might suppress melanomametastasis.[8] However, subsequent work showed that a microRNA located in an intron of the TRPM1 gene, rather than the TRPM1 protein itself, is responsible for the tumor suppressor function.[9][10] The expression of both TRPM1 and the microRNA are regulated by the Microphthalmia-associated transcription factor.[11][12][13][9]
↑Hunter JJ, Shao J, Smutko JS, Dussault BJ, Nagle DL, Woolf EA, Holmgren LM, Moore KJ, Shyjan AW (Nov 1998). "Chromosomal localization and genomic characterization of the mouse melastatin gene (Mlsn1)". Genomics. 54 (1): 116–23. doi:10.1006/geno.1998.5549. PMID9806836.
↑Duncan LM, Deeds J, Hunter J, Shao J, Holmgren LM, Woolf EA, Tepper RI, Shyjan AW (Apr 1998). "Down-regulation of the novel gene melastatin correlates with potential for melanoma metastasis". Cancer Research. 58 (7): 1515–20. PMID9537257.
↑Clapham DE, Julius D, Montell C, Schultz G (Dec 2005). "International Union of Pharmacology. XLIX. Nomenclature and structure-function relationships of transient receptor potential channels". Pharmacological Reviews. 57 (4): 427–50. doi:10.1124/pr.57.4.6. PMID16382100.
↑Miller AJ, Du J, Rowan S, Hershey CL, Widlund HR, Fisher DE (Jan 2004). "Transcriptional regulation of the melanoma prognostic marker melastatin (TRPM1) by MITF in melanocytes and melanoma". Cancer Research. 64 (2): 509–16. doi:10.1158/0008-5472.CAN-03-2440. PMID14744763.
↑Hoek KS, Schlegel NC, Eichhoff OM, Widmer DS, Praetorius C, Einarsson SO, Valgeirsdottir S, Bergsteinsdottir K, Schepsky A, Dummer R, Steingrimsson E (Dec 2008). "Novel MITF targets identified using a two-step DNA microarray strategy". Pigment Cell & Melanoma Research. 21 (6): 665–76. doi:10.1111/j.1755-148X.2008.00505.x. PMID19067971.