The third calmodulin family protein in Tetrahymena. Cloning of the cDNA for Tetrahymena calcium-binding protein of 23 kDa (TCBP-23)

J Biol Chem. 1990 Feb 15;265(5):2514-7.


Recently, we proved the existence of the second calmodulin family protein in Tetrahymena (Tetrahymena calcium-binding protein of 25 kDa, TCBP-25) by analyzing its cDNA (Takemasa, T., Ohnishi, K., Kobayashi, T., Takagi, T., Konishi, K., and Watanabe, Y. (1989) J. Biol. Chem. 264, 19293-19301). During the amino acid sequence determination of TCBP-25, we became aware of the fact that another polypeptide carrying calcium-binding domains of EF-hand type existed in addition to Tetrahymena calmodulin and TCBP-25. This third calmodulin family protein from Tetrahymena was confirmed by isolating its cDNA clones. One of the cloned cDNAs contains 763 nucleotides and encodes a protein that is composed of 207 amino acid residues and has a molecular mass of 23,413 daltons. This predicted protein possesses four EF-hand type calcium-binding domains, so we have designated it as Tetrahymena calcium-binding protein of 23 kDa (TCBP-23). TCBP-23 is similar (35% homology) but clearly different from TCBP-25. The TCBP-23 gene is actively transcribed in vivo as a 0.84-kilobase RNA. Thus, it follows that Tetrahymena cells have three different calmodulin family proteins: calmodulin, TCBP-25 and TCBP-23. These proteins are expected to provide important clues for solving the mechanisms of calcium-dependent phenomena, such as ciliary reversal.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Calcium-Binding Proteins / genetics*
  • Calmodulin / genetics*
  • Cloning, Molecular*
  • DNA / genetics*
  • Gene Library
  • Information Systems
  • Molecular Sequence Data
  • Molecular Weight
  • Oligonucleotide Probes
  • Peptide Mapping
  • Protein Conformation
  • Tetrahymena / genetics*


  • Calcium-Binding Proteins
  • Calmodulin
  • Oligonucleotide Probes
  • DNA

Associated data

  • GENBANK/J05227