title: Calcium-dependent binding of S100C to the N-terminal domain of annexin I.
abstract: The annexin family of proteins is characterized by a conserved core domain that binds to phospholipids in a Ca(2+)-dependent manner. Each annexin also has a structurally distinct N-terminal domain that may impart functional specificity. To search for cellular proteins that interact with the N-terminal domain of annexin I, we constructed a fusion protein consisting of glutathione S-transferase fused to amino acids 2-47 of human annexin I (GST-AINT; AINT = annexin I N-terminal). Extracts from metabolically labeled A431 cells contained a single protein (M(r) approximately 10,000) that bound to GST-AINT in a Ca(2+)-dependent manner. A synthetic peptide corresponding to amino acids 2-18 of annexin I inhibited the binding of the 10-kDa protein to GST-AINT with half-maximal inhibition occurring at approximately 15 microM peptide. In cellular extracts, endogenous annexin I and the 10-kDa protein associated in a reversible Ca(2+)-dependent manner. Experiments with other annexins and with N-terminal truncated forms of annexin I indicated that the 10-kDa protein bound specifically to a site within the first 12 amino acids of annexin I. The 10-kDa protein was purified from human placenta by hydrophobic and affinity chromatography. Amino acid sequence analysis indicated that the 10-kDa protein is the human homologue of S100C, a recently identified member of the S100 subfamily of EF-hand Ca(2+)-binding proteins.
authors.affiliation: Department of Physiology and Biophysics, University of California, Irvine 92717, USA.
authors.forename: W S
authors.initials: WS
authors.lastname: Mailliard
authors.forename: H T
authors.initials: HT
authors.lastname: Haigler
authors.forename: D D
authors.initials: DD
authors.lastname: Schlaepfer
mesh_terms: D000595:Amino Acid Sequence; D017305:Annexin A1 / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D009418:S100 Proteins / Q000378:metabolism*; D017421:Sequence Analysis
chemical_list: D017305:Annexin A1; D002135:Calcium-Binding Proteins; D011993:Recombinant Fusion Proteins; D009418:S100 Proteins; C072337:S100A11 protein, human; D002118:Calcium