Summary: Izumo sperm-egg fusion
Izumo sperm-egg fusion Provide feedback
Izumo is a molecule with a single immunoglobulin (Ig) domain. It is thought that Izumo bind to putative Izumo receptors on the oocyte. Izumo is not detectable on the surface of fresh sperm but becomes exposed only after an exocytotic process, the acrosome reaction, has occurred. Studies have shown that knock-out mice (Izumo-/- males) were sterile despite normal mating behaviour and ejaculation, indicating the importance of the protein in fertilization . There are cysteine residues thought to form a disulphide bridge. Izumo is a typical type I membrane glycoprotein with one immunoglobulin-like domain and a putative N-glycoside link motif (Asn 204) . There is a conserved GCL sequence motif. Izumo expression has been found to be testis-specific [1,2]. This family of proteins is found in eukaryotes and are typically between 193 and 305 amino acids in length.
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Members of the immunoglobulin superfamily are found in hundreds of proteins of different functions. Examples include antibodies, the giant muscle kinase titin and receptor tyrosine kinases. Immunoglobulin-like domains may be involved in protein-protein and protein-ligand interactions. The superfamily can be divided into discrete structural sets, by the presence or absence of beta-strands in the structure and the length of the domains . Proteins containing domains of the C1 and V-sets are mostly molecules of the vertebrate immune system. Proteins of the C2-set are mainly lymphocyte antigens, this differs from the composition of the C2-set as originally proposed . The I-set is intermediate in structure between the C1 and V-sets and is found widely in cell surface proteins as well as intracellular muscle proteins.
The clan contains the following 24 members:A2M Adeno_E3_CR1 Adhes-Ig_like C1-set C2-set C2-set_2 Herpes_gE Herpes_gI Herpes_glycop_D I-set ICAM_N ig Ig_2 Ig_3 Ig_Tie2_1 IZUMO K1 Lep_receptor_Ig Marek_A PTCRA Receptor_2B4 SVA V-set V-set_CD47
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Curation and family details
This family is new in this Pfam release.
|Author:||Coggill P, Hetherington K|
|Number in seed:||8|
|Number in full:||129|
|Average length of the domain:||145.10 aa|
|Average identity of full alignment:||28 %|
|Average coverage of the sequence by the domain:||60.57 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||1|
|Download:||download the raw HMM for this family|
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