In:
European Journal of Biochemistry, Wiley, Vol. 269, No. 14 ( 2002-07), p. 3511-3521
Abstract:
The p25 rum1 is an inhibitor of Cdc2 kinase expressed in fission yeast and plays an important role in cell‐cycle control. As its amino‐acid sequence suggests that p25 rum1 has putative phosphorylation sites for mitogen‐activated protein kinase (MAPK), we investigated the ability of MAPK to phosphorylate p25 rum1 . Direct in vitro kinase assay using GST‐fusion proteins of wild‐type as well as various mutants of p25 rum1 demonstrated that MAPK phosphorylates the N‐terminal portion of p25 rum1 and residues Thr13 and Ser19 are major phosphorylation sites for MAPK. In addition, phosphorylation of p25 rum1 by MAPK revealed markedly reduced Cdc2 kinase inhibitor ability of the protein. Together with the fact that replacement of both Thr13 and Ser19 with Glu, which mimics the phosphorylated state of these residues, also significantly reduces the activity of p25 rum1 as a Cdc2 inhibitor, it was suggested that the phosphorylation of Thr13 and Ser19 negatively regulates the function of p25 rum1 . Further evidence indicates that phosphorylation of Thr13 and Ser19 may retain a negative effect on the function of p25 rum1 even in vivo . Therefore, MAPK may regulate the function of p25 rum1 via phosphorylation of its Thr and Ser residues and thus participate in cell cycle control in fission yeast.
Type of Medium:
Online Resource
ISSN:
0014-2956
,
1432-1033
DOI:
10.1046/j.1432-1033.2002.03033.x
Language:
English
Publisher:
Wiley
Publication Date:
2002
detail.hit.zdb_id:
1398347-7
detail.hit.zdb_id:
1464377-7
SSG:
12