A widely expressed transmembrane serine/threonine kinase that does not bind activin, inhibin, transforming growth factor beta, or bone morphogenic factor

J Biol Chem. 1993 Jun 15;268(17):12719-23.


Molecular cloning of complementary DNAs (cDNA) whose expression products bind activin and transforming growth factor beta (TGF-beta 1 and -beta 2) suggests that transmembrane serine/threonine kinases constitute a new class of signaling molecules. A human liver cell cDNA which codes for a new serine/threonine kinase receptor (SKR1) was identified using degenerate oligonucleotide primers complementary to coding sequence for mouse activin and Caenorhabditis elegans daf-1 serine/threonine receptor kinase subdomains VI and VIII in the polymerase chain reaction. The deduced 509-amino acid product consisted of a cysteine-rich extracellular domain and a cytoplasmic serine/threonine kinase domain which are 10-20 and 40% homologous to the respective domains in the activin and transforming growth factor beta receptor kinases. Cells overexpressing SKR1 exhibited no increase in binding of activin, inhibin, TGF-beta 1, TGF-beta 2, or bone morphogenic factor type 2B. Except for its absence in bone and spleen, SKR1 exhibits a tissue expression pattern similar to the TGF-beta receptor II gene. Similarly, SKR1 is expressed in normal parenchymal cells, endothelial cells, fibroblasts, and tumor-derived epithelial cells. The expression pattern and lack of binding to prototypic members of the TGF-beta 1-5 branch of the TGF-beta superfamily suggests that SKR1 is potentially a receptor for a new member of the TGF-beta branch of the ligand superfamily.

Publication types

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

MeSH terms

  • Activins
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Bone Morphogenetic Proteins
  • Carcinoma, Hepatocellular
  • Cell Line
  • Cloning, Molecular
  • DNA, Neoplasm
  • Gene Expression
  • Growth Substances / metabolism*
  • Humans
  • Inhibins / metabolism
  • Liver / enzymology*
  • Liver Neoplasms
  • Molecular Sequence Data
  • Moths
  • Oligodeoxyribonucleotides
  • Polymerase Chain Reaction
  • Protein Serine-Threonine Kinases / biosynthesis
  • Protein Serine-Threonine Kinases / metabolism*
  • Proteins / metabolism
  • RNA, Neoplasm / isolation & purification
  • RNA, Neoplasm / metabolism
  • Sequence Homology, Amino Acid
  • Substrate Specificity
  • Transfection
  • Transforming Growth Factor beta / metabolism
  • Tumor Cells, Cultured


  • Bone Morphogenetic Proteins
  • DNA, Neoplasm
  • Growth Substances
  • Oligodeoxyribonucleotides
  • Proteins
  • RNA, Neoplasm
  • Transforming Growth Factor beta
  • Activins
  • Inhibins
  • Protein Serine-Threonine Kinases

Associated data

  • GENBANK/L02911
  • GENBANK/M85079
  • GENBANK/X63123