Disease relevance of CABYR

• Moreover, differential expression of CABYR variants may exhibit aberrant expression in brain tumors and cancer cell lines [1].

High impact information on CABYR

• It is presently unknown if proteins encoded by the predicted coding region B of CABYR are translated during spermiogenesis, where they localize, or which CABYR isoforms bind calcium [2].
• CABYR is a highly polymorphic, sperm flagellar calcium-binding protein that is tyrosine as well as serine/threonine phosphorylated during capacitation [2].
• CABYR localizes to the principal piece of the human sperm flagellum in association with the fibrous sheath and is the first demonstration of a sperm protein that gains calcium-binding capacity when phosphorylated during capacitation [3].
• Six variants of CABYR containing two coding regions (CR-A and CR-B) were cloned from human testis cDNA libraries, including five variants with alternative splice deletions [3].
• A motif homologous to the RII dimerization domain of PK-A was present in the N-terminus of CR-A in four CABYR variants [3].

Biological context of CABYR

• These observations confirmed that, despite the presence of the stop codon in CR-A, splice variants containing CR-B are expressed during spermiogenesis and assemble into the fibrous sheath of the principal piece; however, calcium binding occurs only to those CABYR isoforms containing CABYR-A [2].
• In kinase assay, we also showed that CABYR variants act as an ideal substrate for GSK3beta within the extensin-like domain and phosphorylation sites on CABYR were mapped [1].
• The fSP13 bears the closest amino acid similarity to two human sperm proteins: fibrousheathin 2 and testis-specific calcium binding protein 86-VII [4].
• Here we present linkage data from a large German family displaying AD-FSP with anticipation which confirms the existence of the FSP2 locus on chromosome 2p [5].

Associations of CABYR with chemical compounds

• We report here that acidic (pI 4.0) 86-kDa isoforms of a novel, polymorphic, testis-specific protein, designated calcium-binding tyrosine phosphorylation-regulated protein (CABYR), were tyrosine phosphorylated during in vitro capacitation and bound (45)Ca on 2D gels [3].

Physical interactions of CABYR

• Characterization of two non-testis-specific CABYR variants that bind to GSK3beta with a proline-rich extensin-like domain [1].

Other interactions of CABYR

• Molecular characterization showed that CABYR variants formed a dimer with a proline-rich extensin-like domain, which slightly overlapped with GSK3beta-binding site [1].

Analytical, diagnostic and therapeutic context of CABYR

• Interestingly, Northern blot showed that CABYR transcripts were expressed more distinctly in the fetal brain than in the adult brain, suggesting that this protein may play a role during brain development [1].

References