27.3 M phase kinase regulates entry into mitosis MPF (maturation-or M phase- promoting factor)is a dimeric kinase, containing the p34 catalytic subunit and a cyelin regulatory subunit, whose activation triggers the onset of mitosis. 清菜大当
MPF (maturation- or M phasepromoting factor) is a dimeric kinase, containing the p34 catalytic subunit and a cyclin regulatory subunit, whose activation triggers the onset of mitosis. 27.3 M phase kinase regulates entry into mitosis
27.3 M phase kinase regulates entry into mitosis Arrested oocyte (First melosis ■ ◆ =G2) 11 DNA replication/ 88黑=M phase) cleavage cydes ■■■■■■■■■■■的 Ovulation Fertilization DNAreplication Cleavage DNA replication Cleavage MPF level Time 90 120 min ■Injection of egg cytoplasm induces Cyclical rise and fall of MPF . oocyte m aturation ■ 为银■■■数照■■国服◆ ■ Figure 27.6 MPF induces M phase 清菜大当 in early Xenopus development
Figure 27.6 MPF induces M phase in early Xenopus development. 27.3 M phase kinase regulates entry into mitosis
Cell mass doubles 27.3 M phase kinase regulates entry into mitosis State of chrom atin and DNA 2nDNA 2n DNA >2nDNA 4nDNA 2n DNA Figure 27.5 The Phase of cell cycle phases of the cell G1 G2 cycle are controlled 0 hrs 2 14 15 13 20 2224 by discrete events S phase adivator M phase kinase that happen during Activation Acivation Inadivation Gl,at S phase,and Inactvatioactiwation at mitosis. Cyclin synthesis Degradation 清菜大兰
Figure 27.5 The phases of the cell cycle are controlled by discrete events that happen during G1, at S phase, and at mitosis. 27.3 M phase kinase regulates entry into mitosis
27.3 M phase kinase regulates entry into mitosis INTERPHASE MITOSIS Figure 27.7The Thr-167 PPP Thr-14/Tyr-15 P phosphorylation dephosphorylation ThrTyrThr ThrTyrthr ThrTyrThr activity of M phase p34 p34 p34 kinase is regulated by cyclin cyclin cyclin Cyclin phosphorylation, phosphorylation (autocatalytic) dephosphorylation, Thr-14/Tyr-15 Cyclin phosphorylation and protein proteolysis. degradation The 3 phosphorylated amino acids are:Thr- ThrTyrThr 14,Tyr-15,Thr-161. ThrT yr Thr p34 p34 p34 The first two are in the p34/cyclin Cyclin cyclin association cyclin sy nthesis ATP-binding site. 情華大当
Figure 27.7 The activity of M phase kinase is regulated by phosphorylation, dephosphorylation, and protein proteolysis. The 3 phosphorylated amino acids are: Thr- 14, Tyr-15, Thr-161. The first two are in the ATP-binding site. 27.3 M phase kinase regulates entry into mitosis
27.4 Protein phosphorylation and dephosphorylation control the cell cycle Phosphorylation(catalyzed by kinases)and dephosphorylation (catalyzed by phosphatases)are the critical events that regulate the cell cycle.They are used both to control the activities of the regulatory circuit itself and to control the activities of the substrates that execute the decisions of the regulatory circuit. The cell cycle regulatory circuit consists of a series of kinases and phosphatases that respond to external signals and checkpoints by phosphorylating or dephosphorylating the next member of the pathway.The ultimate readout of the circuit is to determine the activity of M phase kinase (or the S phase kinase)by controlling its state of phosphorylation. 清菜大当
Phosphorylation (catalyzed by kinases) and dephosphorylation (catalyzed by phosphatases) are the critical events that regulate the cell cycle. They are used both to control the activities of the regulatory circuit itself and to control the activities of the substrates that execute the decisions of the regulatory circuit. The cell cycle regulatory circuit consists of a series of kinases and phosphatases that respond to external signals and checkpoints by phosphorylating or dephosphorylating the next member of the pathway. The ultimate readout of the circuit is to determine the activity of M phase kinase (or the S phase kinase) by controlling its state of phosphorylation. 27.4 Protein phosphorylation and dephosphorylation control the cell cycle