title: The HMG box of SRY is a calmodulin binding domain.
abstract: The HMG box domain of the testis determining factor, SRY, includes a basic amphiphilic sequence common to calmodulin (CaM) binding proteins. By affinity chromatography, native gel electrophoresis and fluorescence spectroscopy, we show the calcium-dependent binding of SRY to CaM. Binding occurs via the HMG box and an SRY peptide of residues 57-80 binds CaM like the intact domain. SRY/CaM complex formation is specifically inhibited by the SRY DNA binding site sequence, AACAAT, but not a mutated sequence. Fluorescence spectra of the SRY/CaM complex indicate 1:1 stoichiometry and that binding is accompanied by a conformational change in SRY. The A domain of HMG1 also binds CaM and we propose that CaM binding is a property of the wider HMG box family, including SOX and TCF/LEF proteins. These results suggest that CaM may regulate the DNA binding activity of HMG box transcription factors.
authors.affiliation: Department of Genetics, University of Cambridge, UK. vharley@ariel.ucs.unimelb.edu.au
authors.forename: V R
authors.initials: VR
authors.lastname: Harley
authors.forename: R
authors.initials: R
authors.lastname: Lovell-Badge
authors.forename: P N
authors.initials: PN
authors.lastname: Goodfellow
authors.forename: P J
authors.initials: PJ
authors.lastname: Hextall
mesh_terms: D000595:Amino Acid Sequence; D001345:Autoradiography; D001483:Base Sequence; D001665:Binding Sites; D002118:Calcium / Q000494:pharmacology; D002147:Calmodulin / Q000378:metabolism*; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli; D006609:High Mobility Group Proteins / Q000378:metabolism*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D010761:Phosphorus Radioisotopes; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D016324:Sequence Tagged Sites; D051876:Sex-Determining Region Y Protein; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship; D013737:Testis / Q000378:metabolism; D014157:Transcription Factors
chemical_list: D002147:Calmodulin; D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; D009687:Nuclear Proteins; D010761:Phosphorus Radioisotopes; D011994:Recombinant Proteins; C497745:SRY protein, human; D051876:Sex-Determining Region Y Protein; D014157:Transcription Factors; D002118:Calcium