The PI proposes that a major consequence of the calcium rise at fertilization in the sea urchin isthe activation of the calmodulin dependend enzyme, NAD kinase, which produces NADP. The calcium rise also activates Glucose-6-phosphate dehydrogenase, with the result that the NADP is rapidly reduced to NADPH. The resultant increase in the NADPH/NADP ratio then shifts the redox poise of the cell to favor reduction which has consequences for protein synthesis activation. Other regulatory changes emanate from the calcuim rise. The specific goals of the proposed research are to 1) affirm or negate the role of the NADPH change in regulating protein synthesis in vivo and 2) determine whether the NADPH/NADP ratio change is, in addition, acting through alteration of protein disulphide groups, as through a thioredoxin or other protein oxidoreductase system.
