Functional characterization of the phosphorelay protein Mpr1p from Schizosaccharomyces pombe.
Histidine-containing phosphotransfer (HPt) proteins play an essential role in multistep histidine-aspartate phosphorelay signal transduction systems in prokaryotes and eukaryotes. The putative HPt protein in Schizosaccharomyces pombe, Mpr1p (also known as Spy1p), is a 295 amino acid protein that appears to be composed of more than one functional domain. The amino acid sequence of the N-terminal region of Mpr1p lacks homology to other known proteins, whereas the C-terminal domain is predicted to have structural similarity to the Ypd1p HPt protein from Saccharomyces cerevisiae. This study provides both in vitro and in vivo evidence that the C-terminal domain of Mpr1p indeed functions as an HPt protein in shuttling phosphoryl groups from one response regulator domain to another. Furthermore, we find that various deletions of the N-terminal region diminish both the phosphotransfer activity of Mpr1p and its affinity for response regulator domains, suggesting a possible role for the N-terminal domain in HPt-response regulator domain interactions.
Tan
Hui
H
Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019, USA.
Janiak-Spens
Fabiola
F
West
Ann H
AH
D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D006639:Histidine / Q000378:metabolism; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012568:Schizosaccharomyces / Q000201:enzymology*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction / Q000235:genetics
D018797:Cell Cycle Proteins; D010750:Phosphoproteins; D029702:Schizosaccharomyces pombe Proteins; D006639:Histidine; D011494:Protein Kinases; C413334:Mpr1 protein, S pombe