Distinct roles for multiple Src family kinases at fertilization.

Egg activation at fertilization requires the release of Ca2+ from the endoplasmic reticulum of the egg. Recent evidence indicates that Src family kinases (SFKs) function in the signaling pathway that initiates this Ca2+ release in the eggs of many deuterostomes. We have identified three SFKs expressed in starfish (Asterina miniata) eggs, designated AmSFK1, AmSFK2 and AmSFK3.

Identification of a starfish egg PLC-gamma that regulates Ca2+ release at fertilization.

At fertilization, eggs undergo a cytoplasmic free Ca2+ rise, which is necessary for stimulating embryogenesis. In starfish eggs, studies using inhibitors designed against vertebrate proteins have shown that this Ca2+ rise requires an egg Src family kinase (SFK) that directly or indirectly activates phospholipase C-gamma (PLC-gamma) to produce IP3, which triggers Ca2+ release from the egg's endoplasmic reticulum (ER) [reviewed in Semin. Cell Dev.

Function of a sea urchin egg Src family kinase in initiating Ca2+ release at fertilization.

Egg activation at fertilization requires the release of Ca(2+) from the egg's endoplasmic reticulum, and recent evidence has indicated that a Src family kinase (SFK) may function in initiating this signaling pathway in echinoderm eggs. Here, we identify and characterize a SFK from the sea urchin Strongylocentrotus purpuratus, SpSFK1. SpSFK1 RNA is present in eggs, and an antibody made against a SpSFK1 peptide recognizes an approximately 58-kDa egg membrane-associated protein in eggs of S.

Conserved enzymatic production and biological effect of O-acetyl-ADP-ribose by silent information regulator 2-like NAD+-dependent deacetylases.

Silent information regulator 2 (Sir2) family of enzymes has been implicated in many cellular processes that include histone deacetylation, gene silencing, chromosomal stability, and aging. Yeast Sir2 and several homologues have been shown to be NAD(+)-dependent histone/protein deacetylases. Previously, it was demonstrated that the yeast enzymes catalyze a unique reaction mechanism in which the cleavage of NAD(+) and the deacetylation of substrate are coupled with the formation of O-acetyl-ADP-ribose, a novel metabolite.