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. Author manuscript; available in PMC: 2013 Dec 2.
Published in final edited form as: J Biol Chem. 2005 Jul 29;280(38):10.1074/jbc.M501806200. doi: 10.1074/jbc.M501806200

FIGURE 1. Overexpression of Xenopus csp (Xcsp) inhibits PMA-dependent cortical granule exocytosis in Xenopus oocytes.

FIGURE 1

A, individual control oocytes (three separate cells) and csp-overexpressing oocytes (three separate cells injected with csp RNA) were incubated for 30 min with 50 nm PMA, and released cortical granule lectin was detected by Coomassie staining of samples resolved electrophoretically. Cortical granule lectin runs as a broad band between 35 and 45 kDa. Secretion of this protein was inhibited in cells overexpressing csp (+Xcsp). B, overexpression of csp revealed by immunoblot. Extracts of the same cells depicted in A were subjected to immunoblot for csp. Signal in csp overexpressing cells was appreciably stronger than control at the native mass of csp (~33 kDa). In addition, csp overexpressing cells contain unacylated csp at ~27 kDa. C, three control and three csp overexpressing oocytes were challenged with PMA (50 nm). After 30 min the solution was replaced with ionomycin (10 μm) in high Ca2+ solution for 30 min. Released cortical granule lectin was detected as in A.