Cation channels of sperm

The cation channels of sperm also known as Catsper channels or CatSper, are ion channels that are related to the two-pore channels and distantly related to TRP channels. The four members of this family form voltage-gated Ca2+ channels that seem to be specific to sperm. As sperm encounter the more alkaline environment of the female reproductive tract, CatSper channels become activated by the altered ion concentration. These channels are required for proper fertilization.[1] The study of these channels has been slow because they do not traffic to the cell membrane in many heterologous systems.

Cation channels of sperm
Identifiers
SymbolCATSPER
PfamPF15020
InterProIPR028246
Membranome222
cation channel, sperm associated 1
Identifiers
SymbolCATSPER1
IUPHAR388
NCBI gene117144
HGNC17116
OMIM606389
RefSeqNM_053054
UniProtQ8NEC5
Other data
LocusChr. 11 q12.1
cation channel, sperm associated 2
Identifiers
SymbolCATSPER2
IUPHAR389
NCBI gene117155
HGNC18810
OMIM607249
RefSeqNM_172097
UniProtQ96P55
Other data
LocusChr. 15 q13-q15
cation channel, sperm associated 3
Identifiers
SymbolCATSPER3
IUPHAR390
NCBI gene347732
HGNC20819
OMIM609120
RefSeqNM_178019
UniProtQ86XQ3
Other data
LocusChr. 5 q31.2
cation channel, sperm associated 4
Identifiers
SymbolCATSPER4
IUPHAR391
NCBI gene378807
HGNC23220
OMIM609121
RefSeqNM_198137
UniProtQ7RTX7
Other data
LocusChr. 1 p35.3

There are several factors that can activate the CatSper calcium channel, depending on species. In the human, channel is activated by progesterone released by the oocyte. The human CatSper channel is pH-sensitive, and requires a high-pH environment.[2] CatSper plays a key role in mediating hyperactive motility – prior to fertilization, sperm become entrapped within the fingerlike projections of the microvilli of the oviduct. In order for the sperm to fertilize the oocyte, CatSper must be present in order to initiate hyperactive motility, allowing the sperm to escape the microvilli and reach the oocyte for fertilization.[3]

Of the four members of the Catsper family, Catsper1 is found in the primary piece of sperm. Catsper1 plays an important role in evoked Ca2+ entry and regulation of hyperactivation in sperm. Catsper2 is localized in the sperm tail and is responsible for regulation of hyperactivation. Catsper3 and Catsper4 are found in both, the testes and sperm and play an important role in the motility of hyperactivated sperm. Although Catsper seems to play an important role in sperm function, Catspers1-4 null mice have been found to have normal testicular histology, sperm counts and morphology, which is indicative of normal progression of spermatogenesis.[4]

See also

References
  1. Qi H, Moran MM, Navarro B, Chong JA, Krapivinsky G, Krapivinsky L, et al. (January 2007). "All four CatSper ion channel proteins are required for male fertility and sperm cell hyperactivated motility". Proceedings of the National Academy of Sciences of the United States of America. 104 (4): 1219–23. doi:10.1073/pnas.0610286104. PMC 1770895. PMID 17227845.
  2. Sun XH, Zhu YY, Wang L, Liu HL, Ling Y, Li ZL, Sun LB (August 2017). "The Catsper channel and its roles in male fertility: a systematic review". Reproductive Biology and Endocrinology. 15 (1): 65. doi:10.1186/s12958-017-0281-2. PMC 5558725. PMID 28810916.
  3. Carlson AE, Westenbroek RE, Quill T, Ren D, Clapham DE, Hille B, et al. (December 2003). "CatSper1 required for evoked Ca2+ entry and control of flagellar function in sperm". Proceedings of the National Academy of Sciences of the United States of America. 100 (25): 14864–8. Bibcode:2003PNAS..10014864C. doi:10.1073/pnas.2536658100. PMC 299831. PMID 14657352.
  4. Park EH, Kim DR, Kim HY, Park SK, Chang MS (2014). "Panax ginseng induces the expression of CatSper genes and sperm hyperactivation". Asian Journal of Andrology. 16 (6): 845–51. doi:10.4103/1008-682X.129129. PMC 4236327. PMID 24969054.
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