Abstract: Sperm-specific potassium channel, KSper, and sperm-specific calcium channel, CatSper, are the most important specific ion channels on the spermatozoa, which play a key role in the sperm motility, hyperactivation and fertilization. They are regulated by physiological stimuli, such as pH, membrane potential and cyclic adenosine analogues. The KSper protein expressed on testicles and sperm is composed of the main subunit Slo3 and auxiliary subunit LRRC52. It mediates the pH-dependent K+ current (IKSper) produced by mature sperm and regulates the signal transduction process associated with membrane potential, thus influencing male fertility. The CatSper protein expressed exclusively on the principal piece of the sperm tail is composed of CatSper1-4 subunits and 5 auxiliary units, β, γ, δ, ε and ζ. It participates in the spatiotemporal regulation of protein tyrosine-phosphorylation, thus maintaining sperm hyperactivation. Three aspects of Ksper and CatSper, molecular structures, modes of expressions and physiological functions, are summarized in this review.

Key words: Spermatozoa；, Potassium channels；, Calcium channels；, Ion channels；, Sperm capacitation