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Binding of centrins and yeast calmodulin to synthetic peptides corresponding to binding sites in the spindle pole body components Kar1p and Spc110p.

Centrins contain four potential Ca2+ binding sites, known as EF-hands, and have essential functions in centrosome duplication and filament contraction. Here we report that centrins from yeast, green algae, and humans bound with high affinity to a peptide of the yeast centrosomal component Kar1p. Interestingly, centrin binding was regulated by physiological relevant changes in [Ca2+], and this Ca2+ dependence was influenced by acidic amino acids within the Kar1p peptide, which also prevented efficient binding of the related yeast calmodulin. However, a hybrid protein with the third and fourth EF-hands from the yeast centrin Cdc31p and the amino-terminal half from yeast calmodulin behaved more like Cdc31p, indicating that the carboxyl-terminal half of Cdc31p influences binding specificity. Besides Kar1p, centrins bound to a yeast calmodulin binding site, explaining the dosage-dependent suppression of a calmodulin mutant by CDC31. Consistent with an essential role of Ca2+ for centrin functions, mutations in the first or the fourth EF-hands of Cdc31p, impairing the Ca2+-induced conformational change of Cdc31p, resulted in nonfunctional proteins in vivo. Our results suggest that centrins are involved in Ca2+ signaling, likely by influencing the properties of target proteins in response to changes in [Ca2+].

Pubmed ID: 8910460

Authors

  • Geier BM
  • Wiech H
  • Schiebel E

Journal

The Journal of biological chemistry

Publication Data

November 8, 1996

Associated Grants

None

Mesh Terms

  • Amino Acid Sequence
  • Binding Sites
  • Calcium
  • Calcium-Binding Proteins
  • Calmodulin
  • Chromosomal Proteins, Non-Histone
  • Contractile Proteins
  • Cytoskeletal Proteins
  • Fungal Proteins
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Nuclear Proteins
  • Protein Conformation
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Spindle Apparatus