Autophosphorylation of 70 kDa heat shock proteins.
Several members of the 70 kDa heat shock protein group are known to be phosphorylated in vivo and have recently been found to undergo a Ca(2+)-stimulated autophosphorylation. The characteristics of the autophosphorylation reaction with Escherichia coli DnaK the mitochondrial and chloroplast homologs, and the endoplasmic reticulum Bip/Grp78 are discussed. Some common features are a requirement for Ca2+, inhibition by Mg2+ and phosphorylation solely on a threonine residue. Although the role of autophosphorylation of these proteins is not clear, it is known that the level of phosphorylation of some Hsp70 proteins in vivo is responsive to stress and other cellular conditions.
Leustek
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T
Center for Agricultural Molecular Biology, Rutgers University, New Brunswick, NJ 08903.
Amir-Shapira
D
D
Toledo
H
H
Brot
N
N
Weissbach
H
H
D002118:Calcium / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins; D005656:Fungal Proteins / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism*; D010766:Phosphorylation
D029968:Escherichia coli Proteins; D005656:Fungal Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C060153:KAR2 protein, yeast; C063842:dnaK protein, E coli; D002118:Calcium