CDC25B phosphorylation by p38 and MK-2.
CDC25B is one of the three human phosphatases that are involved in the control of the activation of cyclin-dependent kinases. CDC25B participates in regulating entry into mitosis and appears to play a key role in the checkpoint response to DNA injury. CDC25B has been reported to be regulated by a number of kinases and controversial evidence suggests that it is phosphorylated by p38SAPK and/or MAPKAP kinase-2. In this report, we clarify this issue using an approach combining mass spectrometry and the use of specific antibodies against phosphorylated CDC25B residues. We report that MAPKAP kinase-2 phosphorylates CDC25B on multiple sites including S169, S323, S353 and S375, while p38SAPK phosphorylates CDC25B on S249. We show that the S323-phosphorylated form of CDC25B is detected at the centrosome during a normal cell cycle. Since most of these sites are also phosphorylated by several other kinases, our observations highlight the difficulty in characterizing and understanding in vivo phosphorylation patterns.
Lemaire
Matthieu
M
LBCMCP-CNRS UMR5088-IFR109, Institut d'Exploration Fonctionnelle des Génomes, Université Paul Sabatier, Toulouse, France.
Froment
Carine
C
Boutros
Rose
R
Mondesert
Odile
O
Nebreda
Angel R
AR
Monsarrat
Bernard
B
Ducommun
Bernard
B
D000595:Amino Acid Sequence; D045163:Antibodies, Phospho-Specific / Q000276:immunology; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D004789:Enzyme Activation; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010748:Phosphopeptides / Q000378:metabolism; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D020687:cdc25 Phosphatases / Q000737:chemistry / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*; D000099190:MAP-Kinase-Activated Kinase 2
D045163:Antibodies, Phospho-Specific; D018797:Cell Cycle Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010748:Phosphopeptides; D010768:Phosphoserine; D017346:Protein Serine-Threonine Kinases; D020687:cdc25 Phosphatases; D048051:p38 Mitogen-Activated Protein Kinases; D000099190:MAP-Kinase-Activated Kinase 2; C517008:CDC25B protein, human