Expression of temperature-sensitive ion channel TRPM8 in sperm cells correlates with vertebrate evolution.
Transient Receptor Potential cation channel, subfamily Melastatin, member 8 (TRPM8) is involved in detection of cold temperature, different noxious compounds and in execution of thermo- as well as chemo-sensitive responses at cellular levels. Here we explored the molecular evolution of TRPM8 by analyzing sequences from various species. We elucidate that several regions of TRPM8 had different levels of selection pressure but the 4th-5th transmembrane regions remain highly conserved. Analysis of synteny suggests that since vertebrate origin, TRPM8 gene is linked with SPP2, a bone morphogen. TRPM8, especially the N-terminal region of it, seems to be highly variable in human population. We found 16,656 TRPM8 variants in 1092 human genomes with top variations being SNPs, insertions and deletions. A total of 692 missense mutations are also mapped to human TRPM8 protein of which 509 seem to be delateroiours in nature as supported by Polyphen V2, SIFT and Grantham deviation score. Using a highly specific antibody, we demonstrate that TRPM8 is expressed endogenously in the testis of rat and sperm cells of different vertebrates ranging from fish to higher mammals. We hypothesize that TRPM8 had emerged during vertebrate evolution (ca 450 MYA). We propose that expression of TRPM8 in sperm cell and its role in regulating sperm function are important factors that have guided its molecular evolution, and that these understandings may have medical importance.
School of Biological Sciences, National Institute of Science Education and Research, Institute of Physics Campus , Bhubaneswar, Orissa , India.
Rakesh Kumar
RK
Majhi
School of Biological Sciences, National Institute of Science Education and Research, Institute of Physics Campus , Bhubaneswar, Orissa , India ; School of Biotechnology, KIIT University , Bhubaneswar, Orissa , India.
Somdatta
S
Saha
School of Biological Sciences, National Institute of Science Education and Research, Institute of Physics Campus , Bhubaneswar, Orissa , India.
Ashutosh
A
Kumar
School of Biological Sciences, National Institute of Science Education and Research, Institute of Physics Campus , Bhubaneswar, Orissa , India.
Arijit
A
Ghosh
School of Biological Sciences, National Institute of Science Education and Research, Institute of Physics Campus , Bhubaneswar, Orissa , India.
Nirlipta
N
Swain
School of Biotechnology, KIIT University , Bhubaneswar, Orissa , India.
Luna
L
Goswami
Department of Zoology, Government Science College , Chatrapur, Ganjam, Odisha , India.
Pratyush
P
Mohapatra
Department of Veterinary Biochemistry, CVSc & AH, Orissa University of Agriculture & Technology , Bhubaneswar, Orissa , India.
Apratim
A
Maity
School of Biological Sciences, National Institute of Science Education and Research, Institute of Physics Campus , Bhubaneswar, Orissa , India.
Vivek
V
Kumar Sahoo
Department of Genetics & Molecular Biology in Botany, Institute of Botany, Christian-Albrechts-University at Kiel , Kiel, SH , Germany ; Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ) , Heidelberg, BW , Germany.
Abhishek
A
Kumar
School of Biological Sciences, National Institute of Science Education and Research, Institute of Physics Campus , Bhubaneswar, Orissa , India.
Chandan
C
Goswami
Ca2+-signaling; Cold-sensitivity; Molecular evolution; Sperm cells; TRP ion channel; TRPM8; Vertebrate evolution