Greatwall kinase
نویسندگان
چکیده
Mutations in the Drosophila gene greatwall cause improper chromosome condensation and delay cell cycle progression in larval neuroblasts. Chromosomes are highly undercondensed, particularly in the euchromatin, but nevertheless contain phosphorylated histone H3, condensin, and topoisomerase II. Cells take much longer to transit the period of chromosome condensation from late G2 through nuclear envelope breakdown. Mutant cells are also subsequently delayed at metaphase, due to spindle checkpoint activity. These mutant phenotypes are not caused by spindle aberrations, by global defects in chromosome replication, or by activation of a caffeine-sensitive checkpoint. The Greatwall proteins in insects and vertebrates are located in the nucleus and belong to the AGC family of serine/threonine protein kinases; the kinase domain of Greatwall is interrupted by a long stretch of unrelated amino acids.
منابع مشابه
Roles of Greatwall kinase in the regulation of cdc25 phosphatase.
We previously reported that immunodepletion of Greatwall kinase prevents Xenopus egg extracts from entering or maintaining M phase due to the accumulation of inhibitory phosphorylations on Thr14 and Tyr15 of Cdc2. M phase-promoting factor (MPF) in turn activates Greatwall, implying that Greatwall participates in an MPF autoregulatory loop. We show here that activated Greatwall both accelerates ...
متن کاملRegulation of Greatwall kinase during Xenopus oocyte maturation
Greatwall kinase has been identified as a key element in M phase initiation and maintenance in Drosophila, Xenopus oocytes/eggs, and mammalian cells. In M phase, Greatwall phosphorylates endosulfine and related proteins that bind to and inhibit protein phosphatase 2A/B55, the principal phosphatase for Cdk-phosphorylated substrates. We show that Greatwall binds active PP2A/B55 in G2 phase oocyte...
متن کاملGreatwall kinase participates in the Cdc2 autoregulatory loop in Xenopus egg extracts.
Mutations in the Drosophila gene encoding the serine-threonine protein kinase Greatwall have previously been shown to disrupt mitotic progression. To investigate Greatwall's mitotic function, we examined its behavior in Xenopus egg extracts. Greatwall is activated during mitosis by phosphorylation; in vitro evidence indicates that maturation promoting factor (MPF) is an upstream kinase. Convers...
متن کاملGreatwall kinase and cyclin B-Cdk1 are both critical constituents of M-phase-promoting factor
Maturation/M-phase-promoting factor is the universal inducer of M-phase in eukaryotic cells. It is currently accepted that M-phase-promoting factor is identical to the kinase cyclin B-Cdk1. Here we show that cyclin B-Cdk1 and M-phase-promoting factor are not in fact synonymous. Instead, M-phase-promoting factor contains at least two essential components: cyclin B-Cdk1 and another kinase, Greatw...
متن کاملGreatwall is essential to prevent mitotic collapse after nuclear envelope breakdown in mammals.
Greatwall is a protein kinase involved in the inhibition of protein phosphatase 2 (PP2A)-B55 complexes to maintain the mitotic state. Although its biochemical activity has been deeply characterized in Xenopus, its specific relevance during the progression of mitosis is not fully understood. By using a conditional knockout of the mouse ortholog, Mastl, we show here that mammalian Greatwall is es...
متن کاملPolo, Greatwall, and Protein Phosphatase PP2A Jostle for Pole Position
Commitment to mitosis is driven by activation of the Cdk1-Cyclin B protein kinase complex known as Mitosis Promoting Factor (MPF). MPF activation promotes downstream protein kinases that control the formation and function of the mitotic spindle. These kinases include members of the NIMA, Greatwall/Scant, Polo, and Aurora kinase families. Each kinase often phosphorylates multiple targets. Sophis...
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عنوان ژورنال:
- The Journal of Cell Biology
دوره 164 شماره
صفحات -
تاریخ انتشار 2004