Role of cdc2 kinase phosphorylation and conserved N-terminal proteolysis motifs in cytoplasmic polyadenylation-element-binding protein (CPEB) complex dissociation and degradation

• DOI: 10.1042/bj20021462
• Publication Date: 2003-02-24T15:19:23Z
• Authors: George THOM; Nicola MINSHALL; Anna GIT; Joanna ARGASINSKA; Nancy STANDART
• Keywords: Germinal vesicle

Cytoplasmic polyadenylation-element-binding protein (CPEB) is a well-characterized and important regulator of translation maternal mRNA in early development organisms ranging from worms, flies clams to frogs mice. Previous studies provided evidence that clam Xenopus CPEB are hyperphosphorylated at germinal vesicle breakdown (GVBD) by cdc2 kinase, degraded shortly after. To examine the conserved features mediate its modification during meiotic maturation, we microinjected encoding wild-type mutated into oocytes were subsequently allowed mature with progesterone. We observed (i) ectopically expressed phosphorylated GVBD degraded, mirroring fate endogenous protein, (ii) mutation nine Ser/Thr Pro-directed kinase sites prevents phosphorylation degradation (iii) deletion PEST box, lesser extent putative cyclin destruction generates stable version CPEB. conclude both consensus non-consensus targets for PEST-mediated destruction. also show mediates dissociation ribonucleoprotein complexes, prior degradation. Our findings reinforce results obtained Xenopus, have implications other invertebrates including Drosophila, Caenorhabditis elegans Aplysia, which lack boxes.