Sperm arylsulfatase A binds to mZP2 and mZP3 glycoproteins in a nonenzymatic manner
Artikel i vetenskaplig tidskrift, 2012

We have shown previously that sperm surface arylsulfatase A (ASA) of mouse, pig, and human is involved in sperm-egg zona pellucida (ZP) binding. By treating capacitated mouse sperm with A23187 to induce the acrosome reaction, we demonstrated by immunoblotting that ASA also existed in the acrosomal content and on the inner acrosomal membrane. Since mZP2 and mZP3 are known as sperm receptors, whereas mZP1 as a cross-linker of mZP2/mZP3, we determined whether purified ASA bound to mZP2 and mZP3 selectively. The three mZP glycoproteins were purified from solubilized ovarian ZP by size exclusion column chromatography. Immuno-dot blot analyses revealed that purified sperm ASA bound to mZP2 at the highest level followed by mZP3, whereas the binding of ASA to mZP1 was minimal. The results confirmed the physiological significance of sperm ASA in the ZP binding process. The binding of ASA to mZP2 and mZP3 was, however, not dependent on the active site pocket amino acids, Cys69, Lys123, and Lys302, which are pertinent to the capturing of an arylsulfate substrate, since ASA mutant with Ala substitution at these three residues still bound to mZP2 and mZP3. The availability of the active site pocket of ASA bound to the ZP suggested that ASA would still retain enzymatic activity, which might be important for subsequent sperm penetration through the ZP.

Författare

H. Xu

University of Ottawa, Canada

Ottawa Hospital Research Institute

F. Liu

University of Ottawa, Canada

Ottawa Hospital Research Institute

N. Srakaew

Ottawa Hospital Research Institute

Ashok Krishna Chaitanya Koppisetty

Chalmers, Data- och informationsteknik, Datavetenskap

Per-Georg Nyholm

Göteborgs universitet

E. Carmona

Université de Montréal

Hopital Maisonneuve-Rosemont

N. Tanphaichitr

University of Ottawa, Canada

Ottawa Hospital Research Institute

Reproduction

1470-1626 (ISSN) 1741-7899 (eISSN)

Vol. 144 209-19

Styrkeområden

Livsvetenskaper och teknik

Ämneskategorier

Reproduktionsmedicin och gynekologi

DOI

10.1530/REP-11-0338

PubMed

22685254