Treatment of cells with agents that cause DNA damage often results in a delay in G2. There is convincing evidence showing that inhibition of @entity10610 kinase activation is involved in the DNA damage-induced G2 delay. In this study, we have demonstrated the existence of an additional pathway, independent of the @entity10610 kinase activation pathway, that leads to a @entity1167 in @entity2879 -treated cells. Both the X-ray-induced and the @entity2879 -induced @entity1167 were associated with inhibition of the @entity10610 H1 kinase activation pathway as judged by @entity10610 H1 kinase activity and phosphorylation of @entity10609 . @entity5834 treatment restored these activities after either of the treatments. However, the @entity2879 -treated cells did not resume cycling, revealing the presence of an alternative pathway leading to a @entity1167 . To explore the possibility that this additional pathway involved phosphorylation of the MPM-2 epitope that is shared by a large family of mitotic phosphoproteins, we monitored the phosphorylation status of the MPM-2 epitope after DNA damage and after treatment with @entity5834 . Phosphorylation of the MPM-2 epitope was @entity308 in both X-ray and @entity2879 -treated cells, and the @entity308 was reversed by @entity5834 in both cases. The results indicate that the pathway affecting MPM-2 epitope phosphorylation is involved in the G2 delay caused by DNA damage. However, it is not part of the @entity5834 -insensitive pathway leading to a G2 block seen in @entity2879 -treated cells.

The G2 block induced by DNA damage: a @entity5834 -resistant component independent of XXXX , MPM-2 phosphorylation, and H1 kinase activity.

@entity10610 :: ('983', 'Gene') :: ['p34cdc2'] @entity308 :: ('MESH:D003866', 'Disease') :: ['depressed', 'depression'] @entity5834 :: ('MESH:D002110', 'Chemical') :: ['caffeine', 'Caffeine'] @entity2879 :: ('MESH:D005047', 'Chemical') :: ['etoposide'] @entity10609 :: ('995', 'Gene') :: ['cdc25C'] @entity1167 :: ('MESH:D006323', 'Disease') :: ['G2 arrest']
@entity10609 :: (995,Gene) :: ['Cdc25C']
