Plant calreticulin is specifically and efficiently phosphorylated by protein kinase CK2

Biochem Biophys Res Commun. 1996 Apr 25;221(3):498-502. doi: 10.1006/bbrc.1996.0625.


Calreticulin isolated from spinach leaves has been specifically phosphorylated in vitro by protein kinase CK2 while animal calreticulin from rabbit liver is not a substrate of this kinase under the same conditions. Phosphoserine is the only phosphoamino acid detected. High affinity binding (Km = 4.4 microM) and a nearly stoichiometric incorporation of phosphate was determined. Partially purified spinach calreticulin is phosphorylated at the same site(s) by a copurifying protein kinase sharing biochemical properties very similar if not identical to those of mammalian CK2. Other plant calreticulins isolated from Liriodendron tulipifera appear to be also phosphorylated by CK2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Calcium-Binding Proteins / metabolism*
  • Calreticulin
  • Casein Kinase II
  • Molecular Sequence Data
  • Phosphorylation
  • Protein-Serine-Threonine Kinases / metabolism*
  • Ribonucleoproteins / metabolism*
  • Sequence Homology, Amino Acid
  • Spinacia oleracea / metabolism*
  • Starfish
  • Substrate Specificity


  • Calcium-Binding Proteins
  • Calreticulin
  • Ribonucleoproteins
  • Casein Kinase II
  • Protein-Serine-Threonine Kinases