TRPM1

In addition to the retina, TRPM1 is also expressed in melanocytes of the skin. In melanoma, the expression of TRPM1 in tumor cells is inversely correlated with the aggressiveness of the melanoma. However, subsequent work has shown that it is not the TRPM1 protein itself, but a microRNA localized in an intron of the TRPM1 gene that is responsible for tumor suppression. Loss of TRPM1 mRNA expression thus appears to be a critical factor in the progression of melanoma to a more malignant, metastatic phenotype (Erickson LA et al. 2009; Brożyna AA et al. 2017).

Both TRPM1 and microRNA expression are regulated by the so-called microphthalmia-associated transcription factor (MIT)-related factor.

Mutations in TRPM1 are associated with congenital stationary night blindness (CSNB) in humans, in which rod function is absent and patients suffer from night blindness in early childhood (Irie S et al. 2014).

In animals, mutations are associated with coat spotting in Appaloosa horses, which may also suffer from Congenital Stationary Night Blindness (CSNB).

1. Barley NF et al.(2001) Epithelial calcium transporter expression in human duodenum. Am. J. Physiol. Gastrointest Liver Physiol 280: G285-G290.
2. Brożyna AA et al. (2017) TRPM1 (melastatin) expression is an independent predictor of overall survival in clinical AJCC stage I and II melanoma patients. J Cutan Pathol 44: 328-337.
3. Erickson LA et al (2009) TRPM1 (melastatin-1/MLSN1) mRNA expression in Spitz nevi and nodular melanomas. Mod Pathol 22:969-976.
4. Irie S et al (2014) Handb Exp Pharmacol 222:387-402.
5. Lim JY et al. (2015) Biological Roles of Resolvins and Related Substances in the Resolution of Pain. BioMed Research International doi:10.1155/2015/830930.
6. Michalick L et al (2020) TRPV4-A Missing Link Between Mechanosensation and Immunity. Front Immunol 11:413.
7. Moran MM et al. (2018) Targeting nociceptive transient receptor potential channels to treat chronic pain: current state of the field. Br J Pharmacol 175:2185-2203.
8. Schneider FM et al (2015) Properties and functions of TRPM1 channels in the dendritic tips of retinal ON-bipolar cells. Eur J Cell Biol. 94: 420-427.
9. Varin J et al. (2020) Identification and characterization of novel TRPM1 autoantibodies from serum of patients with melanoma-associated retinopathy. PLoS One 15(4):e0231750.
10. Wang Y et al. (2017) Targeting Transient Receptor Potential Canonical Channels for Diseases of the Nervous System. Curr Drug Targets.18:1460-1465.