ABSTRACT
TRPM1 (otherwise known as melastatin) was the rst TRPM identied and is considered a marker for metastasized
melanomas. TRPM2 has a unique Nudix hydrolase domain that is homologous to the ADP pyrophosphatase NUDT9, which serves as a binding site for channel activation by adenine nucleotides, and the channel likely serves as a cellular sensor of oxidation. TRPM3 is an enigmatic channel in that it has several alternatively spliced variants that may serve a role in cellular responses to hypotonicity. TRPM4 and TRPM5 are the only members of the TRP channel family that are selective for only monovalent cations and do not permeate Ca2+. However, both are activated by intracellular Ca2+, serving as transduction channels downstream of increased cellular Ca2+ levels. Like TRPM2, TRPM6 and TRPM7 possess both ion channel and enzymatic domains, in this case atypical protein kinases that are structurally similar to protein kinase A (PKA). ese channels appear to serve as sensors of the levels of intracellular Mg2+ and are inhibited under conditions of normal divalent cation
Contents 29.1 Introduction 433 29.2 TRPM1 434
29.2.1 Molecular structure 434 29.2.2 Cellular function 434
29.3 TRPM2 436 29.3.1 Molecular structure 437 29.3.2 Cellular function 437
29.4 TRPM3 437 29.4.1 Molecular structure 438 29.4.2 Cellular function 438
29.5 TRPM4 438 29.5.1 Molecular structure 438 29.5.2 Cellular function 439
29.6 TRPM5 439 29.6.1 Molecular structure 439 29.6.2 Cellular functions 440
29.7 TRPM6 440 29.7.1 Molecular structure 440 29.7.2 Cellular functions 441
29.8 TRPM7 441 29.8.1 Molecular structure 441 29.8.2 Cellular function 441
29.9 TRPM8 442 29.9.1 Molecular structure 442 29.9.2 Cellular function 443
Acknowledgment 444 References 444
concentrations suggesting they are important for general Mg2+ homeostasis. TRPM8 was rst identied in prostate, in which it is proposed to be an androgen-responsive channel, but the channel chiey serves as a sensor of cold temperatures in the peripheral nervous system. us, TRPM channels are a diverse array of ion channels key in a number of cellular processes. e following addresses salient points on each channel, putting them in the context of molecular and structural dierences between each protein, as well as describes what is known of their basic cellular functions at this time.
