Sperm equatorial segment protein 1 (SP-ESP, Equatorial segment protein, ESP, glycosylated 38 kD sperm protein C-7/8) (SPESP1)

Structure

belongs to the SPESP1 family

Compartment

• acrosome
• small proacrosomal granules (during Golgi phase)
• enlarged acrosomal vesicles (during cap phase)
• acrosome (during the elongating phase)
• equatorial segment of acrosome (during maturation phase)

Expression

• highly expressed in testis, where it is localized in the acrosome of postmeiotic stages of spermiogenesis (round & elongating spermatids & in ejaculated spermatozoa) (at protein level)
• poorly expressed in placenta & fetal lung

More general terms

• testis-specific protein
• glycoprotein

Database

• UniProt: http://www.uniprot.org/uniprot/Q6UW49.html