The RING-finger protein haprin: domains and function in the acrosome reaction.
The RBCC (RING finger, B-box type zinc finger, coiled-coil domain) motif family contains a large number of proteins implicated in many cellular processes, including vesicle exocytosis. The acrosome reaction, the sperm exocytotic event that is required for fertilization, involves essentially the same process of intracellular membrane fusions as vesicular exocytosis in somatic cells. We have previously isolated a haploid-germ-cell-specific gene designated haprin, which encodes a RBCC motif protein that plays a role in the acrosome reaction of sperm by mediating protein complex formation via the RBCC motif. In this review, we describe the potential role of Haprin in the molecular mechanisms of acrosome reaction, as compared with some other RBCC proteins. The conserved structure and localization of the Haprin protein in human and mouse suggest an indispensable role for Haprin in the functioning of mammalian sperm.
Kitamura
Kouichi
K
Department of Science for Laboratory Animal Experimentation, Research Institute for Microbial Disease, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Tanaka
Hiromitsu
H
Nishimune
Yoshitake
Y
D000177:Acrosome / Q000737:chemistry* / Q000502:physiology*; D020101:Acrosome Reaction / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D008297:Male; D020619:Methylococcus capsulatus / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D013094:Spermatozoa / Q000737:chemistry / Q000502:physiology
C079141:haprin