Mammalian growth-associated H1 histone kinase: a homolog of cdc2+/CDC28 protein kinases controlling mitotic entry in yeast and frog cells.

Abstract

Mammalian growth-associated Hi histone kinase, an enzyme whose activity is sharply elevated at mitosis, is similar to cdc2+ protein kinase from Schizosaccharomyces pombe and CDC28 protein kinase from Saccharomyces cerevisiae with respect to immunoreactivity, molecular size, and specificity for phosphorylation sites in Hi histone. Phosphorylation of specific growth-associated sites in HI histone is catalyzed by yeast cdc2+1CDC28 kinase, as shown by the in vitro thermal lability of this activity in extracts prepared from temperature-sensitive mutants. In addition, highly purified Xenopus maturation-promoting factor catalyzes phosphorylation of the same sites in Hi as do the mammalian and yeast kinases. The data indicate that growth-associated Hi kinase is encoded by a mammalian homolog of cdc2+ICDC28 protein kinase, which controls entry into mitosis in yeast and frog cells. Since Hi histone is known to be an in vivo substrate of the mammalian kinase, this suggests that phosphorylation of Hi histone or an Hi histone counterpart is an important component of the mechanism for entry of cells into mitosis.Among the protein phosphorylation reactions which occur in eucaryotic cells, one of the most prominent is the exten-

The pk-1 Gene of Autographa Californica Multinucleocapsid Nuclear Polyhedrosis Virus Encodes a Protein Kinase

“…Histone H1 is known to be phosphorylated by the cell cycle kinases cdc2+/CDC28 (Langan et al, 1989). Phosphorylation of histone H1 by the cell cycle kinases occurs in two stages, the first in S phase when the cell commits to a new round of division, and again at the start of mitosis in order to condense the DNA into the 30 nm fibre form.…”

Identification of a Spindlin homolog in gibel carp (Carassius auratus gibelio)

“…In this study, we further demonstrate from the GST pull-down assay that CagSpin directly or indirectly associates with h-tubulin, and therefore provide the first biochemical evidence for the specific interaction of Spindlin protein and h-tubulin, the microtubule component. Interestingly, some important proteins that play crucial functions during oocyte maturation and egg fertilization, such as p39 mos (Zhou et al, 1992;Haccard et al, 1993;Verlhac et al, 1996), p34 cdc2 of metaphase promoting factor (MPF) (Langan et al, 1989;Peter et al, 1990;Verde et al, 1990;Zhou et al, 1991Zhou et al, , 1992, cyclin B, the regulatory component of MPF (Pines and Hunter, 1991;Ookata et al, 1993), MAP kinase (Verlhac et al, 1993) and PKC (Page Baluch et al, 2004), have been also confirmed to associate with microtubules. Interestingly, three putative PKC phosphorylation sites have been revealed in the CagSpin sequence (Fig.…”

Human cDNAs encoding homologs of the small p34Cdc28/Cdc2-associated protein of Saccharomyces cerevisiae and Schizosaccharomyces pombe.

“…MPF has been purified from Xenopus and starfish oocytes and has been shown to contain, as an essential component, the Cdc2/Cdc28 protein kinase {Gautier Lohka et al 1988;Labbe et al 1989a). It also appears that an activity known as growth-associated histone H1 kinase, which is present during mitosis in a number of organisms (Bradbury et al 1974;Chambers et al 1983), contains the Cdc2/Cdc28 protein and is likely to be identical to MPF (Arion et al 1988;Labbe et al 1988Labbe et al , 1989aBrizuela et al 1989;Langan et al 1989}.…”