CHUK, a new member of the helix-loop-helix and leucine zipper families of interacting proteins, contains a serine-threonine kinase catalytic domain

Cell Mol Biol Res. 1995;41(6):537-49.


We have identified a new member of the helix-loop-helix (H-L-H) and leucine zipper gene families via a reverse transcriptase-polymerase chain reaction based strategy. This new gene, CHUK (conserved helix-loop-helix ubiquitous kinase), may represent the founding member of a new class of interacting chimeric proteins. The nucleotide sequence of a near full-length murine CHUK cDNA clone revealed an encoded polypeptide specifying: a carboxyl-terminal H-L-H domain, an amino terminal serine-threonine kinase catalytic domain, and a leucine zipper-like amphipathic alpha-helix juxtaposed in between the H-L-H and kinase domains. CHUK is highly conserved in evolution and ubiquitously expressed in diverse types of established cell lines, whereas it is differentially expressed in normal murine tissues. The structural features of the CHUK polypeptide suggest that its putative kinase activity may be targetted to H-L-H and/or leucine zipper transcription factors. Alternatively, the dual amphipathic a helices may serve to control its intrinsic kinase activity by interactions with other cellular factors. CHUK may provide new insights into the regulated transmission of cytoplasmic signals to specific nuclear factors manifesting rapid alterations in patterns of cellular gene expression.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Binding Sites
  • Biological Evolution
  • Catalysis
  • Cattle
  • Chickens
  • Cloning, Molecular
  • Conserved Sequence
  • Cricetinae
  • DNA, Complementary / analysis
  • Dogs
  • Haplorhini
  • Helix-Loop-Helix Motifs / genetics*
  • Humans
  • I-kappa B Kinase
  • Leucine Zippers / genetics*
  • Mice
  • Molecular Sequence Data
  • Polymerase Chain Reaction
  • Protein Serine-Threonine Kinases / chemistry
  • Protein Serine-Threonine Kinases / genetics*
  • Rabbits
  • Rats


  • DNA, Complementary
  • Protein Serine-Threonine Kinases
  • CHUK protein, human
  • Chuk protein, mouse
  • I-kappa B Kinase
  • IKBKB protein, human
  • IKBKE protein, human
  • Ikbkb protein, mouse
  • Ikbke protein, mouse

Associated data

  • GENBANK/U12473
  • GENBANK/U22512