Roles of several domains identified in the primary structure of salt-inducible kinase (SIK).
Salt-inducible kinase (SIK), a 776 amino acids-protein, contains a kinase domain in the NH2-terminal 278 amino acid residues, and the biological functions of its COOH-terminal half have yet to be clarified. Here we describe the roles played by several domains in the SIK molecule. K56, an amino acid residue found in a region similar to the ATP-binding loop of other protein kinases, was essential for carrying out the SIKs phosphorylation reaction. An SNF-1 homology domain (SNH), identified at a peptide stretch from the 317th to the 346th residues, and conserved among all the sucrose-nonfermenting-1 protein kinase (SNF-1) family protein kinases, was important to maintain the SIKs protein conformation in the cells. S577, an amino acid residue found in one of three consensus PKA-dependent phosphorylation motifs, was indeed phosphorylated by PKA. The phosphorylated SIK was found to move out of the nucleus to the cytoplasm.
Horike
Nanao
N
Department of Molecular Physiological Chemistry, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka, 565-0871 Japan.
Takemori
Hiroshi
H
Katoh
Yoshiko
Y
Doi
Junko
J
Okamoto
Mitsuhiro
M
D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000502:physiology*; D017434:Protein Structure, Tertiary / Q000502:physiology
D017346:Protein Serine-Threonine Kinases; C120299:Sik1 protein, rat; D017868:Cyclic AMP-Dependent Protein Kinases