A role for CKII phosphorylation of the Cactus PEST domain in dorsoventral patterning of the Drosophila embryo

Zhi Ping Liu, Rene L. Galindo, Steven A. Wasserman

Research output: Contribution to journalArticle

56 Scopus citations


Regulated proteolysis of Cactus, the cytoplasmic inhibitor of the Rel- related transcription factor Dorsal, is an essential step in patterning of the Drosophila embryo. Signal-induced Cactus degradation frees Dorsal for nuclear translocation on the ventral and lateral sides of the embryo, establishing zones of gene expression along the dorsoventral axis. Cactus stability is regulated by amino-terminal serine residues necessary for signal responsiveness, as well as by a carboxy-terminal PEST domain. We have identified Drosophila casein kinase II (CKII) as a Cactus kinase and shown that CKII specifically phosphorylates a set of serine residues within the Cactus PEST domain. These serines are phosphorylated in vivo and are required for wild-type Cactus activity. Conversion of these serines to alanine or glutamic acid residues differentially affects the levels and activity of Cactus in embryos, but does not inhibit the binding of Cactus to Dorsal. Taken together, these data indicate that wild-type axis formation requires CKII-catalyzed phosphorylation of the Cactus PEST domain.

Original languageEnglish (US)
Pages (from-to)3413-3422
Number of pages10
JournalGenes and Development
Issue number24
StatePublished - Dec 15 1997



  • Dorsal
  • NF-κB
  • Proteolysis
  • Rel
  • Signal transduction

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology

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