PUBLICATION

The Golgi "casein kinase" Fam20C is a genuine "phosvitin kinase" and phosphorylates polyserine stretches devoid of the canonical consensus

Authors
Cozza, G., Moro, E., Black, M., Marin, O., Salvi, M., Venerando, A., Tagliabracci, V.S., Pinna, L.A.
ID
ZDB-PUB-181103-6
Date
2018
Source
The FEBS journal   285(24): 4674-4683 (Journal)
Registered Authors
Moro, Enrico
Keywords
Fam20C, Vitellogenesis, phosphoserine stretches, phosvitin, sphingolipid signaling
MeSH Terms
  • Amino Acid Sequence
  • Animals
  • Casein Kinase I/metabolism*
  • Chickens
  • Consensus
  • Extracellular Matrix Proteins/metabolism*
  • Golgi Apparatus/enzymology*
  • Humans
  • Peptides/metabolism*
  • Phosphoproteins/metabolism*
  • Phosphorylation
  • Phosvitin/metabolism*
  • Sequence Homology
  • Zebrafish
PubMed
30387551 Full text @ FEBS J.
Abstract
Egg yolk phosvitins, generated through the fragmentation of vitellogenins, are among the most heavily phosphorylated proteins ever described. Despite the early discovery in 1900 that chicken phosvitin is a phosphoprotein and its subsequent employment as an artificial substrate for a number of protein kinases, the identity of the enzyme(s) responsible for its phosphorylation remained a matter of conjecture until present. Here we provide evidence that phosvitin phosphorylation is catalyzed by Fam20C, an atypical protein kinase recently identified as the genuine casein kinase and responsible for the phosphorylation of many other secreted proteins at residues specified by the S-x-E/pS consensus. Such a conclusion is grounded on the following observations: i) the levels of Fam20C and phosphorylated vitellogenin rise in parallel upon treatment of zebrafish with oestrogens; ii) Zebrafish phosvitin is readily phosphorylated upon coexpression in U2OS cells with Fam20C, but not with its catalytically inactive mutant; iii) a peptide reproducing a stretch of 12 serines, which are phosphorylated in chicken phosvitin despite lacking the C terminal priming motif S-x-E, is efficiently phosphorylated by both recombinant and native Fam20C. The last finding expands the repertoire of potential targets of Fam20C to include several proteins known to harbour (p-Ser)n clusters not specified by any known kinase consensus. This article is protected by copyright. All rights reserved.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping