ZP3

The zona pellucida is an extracellular matrix that surrounds the oocyte and early embryo. It is composed primarily of three or four glycoproteins with various functions during fertilization and preimplantation development. The protein encoded by this gene is a structural component of the zona pellucida and functions in primary binding and induction of the sperm acrosome reaction. The nascent protein contains a N-terminal signal peptide sequence, a conserved ZP domain, a C-terminal consensus furin cleavage site, and a transmembrane domain. It is hypothesized that furin cleavage results in release of the mature protein from the plasma membrane for subsequent incorporation into the zona pellucida matrix. However, the requirement for furin cleavage in this process remains controversial based on mouse studies. A variation in the last exon of this gene has previously served as the basis for an additional ZP3 locus; however, sequence and literature review reveals that there is only one full-length ZP3 locus in the human genome. Another locus encoding a bipartite transcript designated POMZP3 contains a duplication of the last four exons of ZP3, including the above described variation, and maps closely to this gene.

Full Name

zona pellucida sperm-binding protein 3

Function

Component of the zona pellucida, an extracellular matrix surrounding oocytes which mediates sperm binding, induction of the acrosome reaction and prevents post-fertilization polyspermy. The zona pellucida is composed of 3 to 4 glycoproteins, ZP1, ZP2, ZP3, and ZP4. ZP3 is essential for sperm binding and zona matrix formation.

Biological Process

Biological Process binding of sperm to zona pellucida Source:UniProtKB2 Publications
Biological Process blastocyst formation Source:UniProtKB
Biological Process egg coat formation Source:UniProtKB
Biological Process humoral immune response mediated by circulating immunoglobulin Source:UniProtKB
Biological Process negative regulation of binding of sperm to zona pellucida Source:UniProtKB1 Publication
Biological Process negative regulation of DNA-templated transcription Source:UniProtKB
Biological Process oocyte development Source:UniProtKB
Biological Process positive regulation of acrosomal vesicle exocytosis Source:UniProtKB1 Publication
Biological Process positive regulation of acrosome reaction Source:UniProtKB3 Publications
Biological Process positive regulation of antral ovarian follicle growth Source:UniProtKB
Biological Process positive regulation of DNA-templated transcription Source:UniProtKB
Biological Process positive regulation of humoral immune response Source:UniProtKB1 Publication
Biological Process positive regulation of inflammatory response Source:UniProtKB
Biological Process positive regulation of interleukin-4 production Source:UniProtKB
Biological Process positive regulation of leukocyte migration Source:UniProtKB
Biological Process positive regulation of ovarian follicle development Source:UniProtKB
Biological Process positive regulation of T cell proliferation Source:UniProtKB
Biological Process positive regulation of type II interferon production Source:UniProtKB
Biological Process positive regulation of type IV hypersensitivity Source:UniProtKB

Cellular Location

Processed zona pellucida sperm-binding protein 3
Zona pellucida
Cell membrane

Involvement in disease

Oocyte maturation defect 3 (OOMD3):
An autosomal dominant infertility disorder characterized by abnormal oocytes that lack the zona pellucida, and oocytes degeneration.

Topology

Extracellular: 23-387
Helical: 388-408
Cytoplasmic: 409-424

PTM

Proteolytically cleaved before the transmembrane segment to yield the secreted ectodomain incorporated in the zona pellucida.
N-glycosylated.
O-glycosylated; removal of O-linked glycans may play an important role in the post-fertilization block to polyspermy.