A novel binding protein for a member of CyP40-type Cyclophilins: N.crassa CyPBP37, a growth and thiamine regulated protein homolog to yeast Thi4p.
Cyclophilins belong to the family of peptidyl-prolyl cis/trans isomerases (PPIases), which are ubiquitous and highly conserved enzymes capable of cis/trans isomerizing Xaa-Pro peptide bonds. Members of the CyP40-type cyclophilins have originally been described as components of hormone receptor complexes. Here, we describe NcCyP41, a CyP40 ortholog from Neurospora crassa, its expression in Escherichia coli and subsequent purification. Characterization of NcCyP41 reveals that it is a heat shock protein, which is active as a cyclosporin A-sensitive PPIase. Affinity chromatography using immobilized recombinant NcCyP41 yielded two major NcCyP41-binding proteins: Hsp80 (a Hsp90 ortholog from N.crassa) and CyPBP37. CyPBP37 has not been described. In addition, this is the first record describing an interaction between a member of Cyp40-type cyclophilins and of CyPBP37-type proteins, respectively. CyPBP37 expression is repressed by thiamine and in the stationary phase in N.crassa. CyPBP37 is present in different isoforms. The expression of a CyPBP37 ortholog in yeast, Thi4p, is diminished in a mutant lacking one of the two CyP40 orthologs (Cpr7p). In addition, the DeltaCpr7p deletion mutant shows a thiamine-dependent growth defect. We conclude that, in yeast, Cpr7p and Thi4p interact functionally.
Faou
Pierre
P
Institut für Biochemie und Molekularbiologie der Universität Freiburg, Hermann-Herder-Strasse 7, D-79104 Freiburg, Germany.
Tropschug
Maximilian
M
D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology; D021983:Cyclophilins; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000201:enzymology* / Q000378:metabolism; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013831:Thiamine / Q000378:metabolism*; D000097322:Peptidyl-Prolyl Isomerase D
D002352:Carrier Proteins; D021983:Cyclophilins; D005656:Fungal Proteins; D020033:Protein Isoforms; D013831:Thiamine; C114456:PPID protein, human; D000097322:Peptidyl-Prolyl Isomerase D