Premium
Molecular and binding characteristics of IP3 receptors in bovine spermatozoa
Author(s) -
Minelli Alba,
Allegrucci Cinzia,
Rosati Roberto,
Mezzasoma Isabella
Publication year - 2000
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/1098-2795(200008)56:4<527::aid-mrd11>3.0.co;2-r
Subject(s) - receptor , biology , inositol phosphate , inositol , microbiology and biotechnology , biochemistry , second messenger system , endocrinology , medicine
We have shown the presence of inositol 1,4,5‐triphosphate (IP3) receptors in bovine spermatozoa. These receptors are mainly localized and functionally associated with the acrosome region. Molecular characterization of these bovine IP3 receptors has shown that the functional size of the IP3 binding domain is a protein of 66 ± 2 kDa, in agreement with the size of both bovine adrenal cortex and bovine adrenal medullar chromaffin cells IP3 receptors. In contrast, bovine cerebellum IP3 receptor displays molecular weight of 220 ± 5 kDa, a value in agreement with data in the literature. Bovine IP3 receptors have a one‐affinity state characterized by a low affinity (K d 750 nM) and a relatively high density (7.5 pmol/mg protein). They are functional and release internal calcium upon the binding of the second messenger. Moreover, the finding that the specific A1 adenosine receptor agonist R‐PIA elicits almost the same effect as IP3 might be of some help in understanding the physiological role of these inhibitory adenosine receptors in mammalian spermatozoa. Mol. Reprod. Dev. 56:527–533, 2000. © 2000 Wiley‐Liss, Inc.