A sperm-specific voltage-gated calcium channel that controls the intracellular calcium ion concentration and, thereby, the swimming behavior of sperm. Consists of a heteromeric tetramer surrounding a calcium ion- selective pore. May also contain additional auxiliary subunits. [GOC:sp, PMID:17478420, PMID:21224844, PMID:22354039]
The directed, self-propelled movement of a cilium (aka flagellum) that contributes to the movement of a flagellated sperm. [GO_REF:0000060, GOC:cilia, GOC:krc, GOC:TermGenie, PMID:26680031]
The segment of the sperm flagellum where the mitochondrial sheath ends, and the outer dense fibers (ODFs) associated with outer axonemal doublets 3 and 8 are replaced by the 2 longitudinal columns of the fibrous sheath (FS) which run the length of the principal piece and are stabilized by circumferential ribs. The principal piece makes up ~2/3 of the length of the sperm flagellum and is defined by the presence of the FS and of only 7 (rather than 9) ODFs which taper and then terminate near the distal end of the principal piece. [GOC:cjm, MP:0009836]
A process required for sperm to reach fertilization competence. Sperm undergo an incompletely understood series of morphological and molecular maturational processes, termed capacitation, involving, among other processes, protein tyrosine phosphorylation and increased intracellular calcium. [GOC:jid, ISBN:978-3-642-58301-8, PMID:11820818]