- Peptide (C)RALFQDSDPKRFQN, corresponding to amino acid residues 508-521 of mouse CatSper1 (Accession Q91ZR5). 3rd extracellular loop.
- Western blot analysis of rat (lanes 1 and 3) and mouse (lanes 2 and 4) testis lysates:1. Anti-CatSper1 (extracellular) Antibody (#ACC-301), (1:200).
2. Anti-CatSper1 (extracellular) Antibody, preincubated with CatSper1 (extracellular) Blocking Peptide (#BLP-CC301).
- Ren, D. and Xia, J. (2010) Physiology 25, 165.
- Darszon, A. et al. (2011) Physiol. Rev. 91, 1305.
- Kirichok, Y. and Lishko, P.V. (2011) Mol. Hum. Reprod. 17, 478.
- Visconti, P.E. et al. (2011) Asian J. Androl. 13, 395.
- Reid, A.T. et al. (2011) Asian J. Androl. 13, 88.
- Yoshida, M. and Yoshida, K. (2011) Mol. Hu. Repro. 17, 457.
Capacitation is the final stage of spermatozoon maturation which eventually enables it to bind the zona pellucida (ZP) - a thick layer of glycoproteins surrounding the oocyte1-3. It occurs in the fallopian tubes of the female reproductive tract and is preceded by spermatogenesis (testes) and epididymal maturation (epididymis)3,4. Capacitation is accompanied by drastic morphological and functional alterations, such as membrane hyperpolarization, changes in membrane lipid composition, intracellular alkalinization, increased level of protein tyrosine phosphorylation by cAMP-dependent PKA, and elevated intracellular concentrations of Ca2+ ([Ca2+]i) and pHi1,2, which render the sperm chemotaxis-responsive and hyperactive6,7. Increased flagellar bend, triggered by Ca2+ signaling, produces asymmetrical, whiplash-like motility pattern that provides the sperm with significantly stronger swimming thrust1-3. Hyperactivity, together with the eruption of hydrolytic enzymes from the sperm's acrosome vesicle facilitate the disruption of the ZP matrix and make way for the sperm to enter the egg cytoplasm1-7.
CatSper (cation channel of spermatozoa) is a sperm-specific Ca2+ channel located explicitly in the spermatozoon flagellum2. It mediates flagellar hyperactivity7, and is chemotactically responsive to progesterone8. CatSper is composed of 4 pore-forming subunits (CatSper1-4) with 6 transmembrane (TM) domains each, and of 3 auxiliary subunits: CatSperβ (2 TM domains), CatSperγ and CatSperδ (1 TM domain each)1, 2. While all four CatSper proteins are necessary for the channel's function (and hence male fertility)9, each is synthesized independently. Trafficking to the flagellum requires the cooperation of all subunits1,3.
CatSper1, the first identified subunit of the channel, is highly homologous to CaV channels; a voltage sensor domain (S1-S4) containing enough positively charged residues to confer weak voltage sensitivity to the channel2. Furthermore, its histidine-rich, intracellular amino terminus likely serves as the pH sensor necessary to induce hyperactivation (by permitting an influx of Ca2+)3. Indeed, intracellular alkaline pH (7.9-8.5) was shown to efficiently hyper-activate CatSper channels7.
Species reactivity key:
Anti-CatSper1 (extracellular) Antibody (#ACC-301) is a highly specific antibody directed against an epitope of the mouse protein. The antibody can be used in western blot analysis. The antibody recognizes an extracellular epitope and is thus ideal for detecting CatSper1 in living cells. It has been designed to recognize CatSper1 from mouse, rat and human samples.