Fig. 6. Confirmation of tyrosine phosphorylation and surface localisation of erp99 and hsp60 on mouse spermatozoa. (A) Cauda epididymal spermatozoa were either freshly isolated (lanes 1 and 3) or capacitated for 90 minutes in BWW–Ca²⁺+Sr²⁺+ptx+cAMP (lanes 2 and 4). CHAPS detergent lysates (5 µg protein/lane) (lanes 1 and 2) and purified surface-protein extracts from 100 µg lysate (lanes 3 and 4) were prepared, resolved by SDS-PAGE and immunoblotted with anti-hsp60 and anti-erp99 monoclonal antibodies. (B) Cauda epididymal spermatozoa were capacitated for 90 minutes in BWW. Proteins were solubilised, resolved by two-dimensional electrophoresis and immunoblotted with anti-phosphotyrosine (a), anti-erp99 (b) and anti-hsp60 (c) antibodies.