Sequence of the phosphorylation and dephosphorylation events over the Biology Diagrams Phosphorylation of about 75% of the protein kinases they identified was upregulated more than twofold in M phase, suggesting that cell-cycle progression involves extensive rearrangements of
This is achieved by rising CDK activity and the differential sensitivity of substrates to CDK activity over a wide dynamic range. This is combined with rapid phosphorylation turnover to generate clearly resolved substrate-specific activity thresholds, which in turn ensures the appropriate ordering of downstream cell-cycle events.
The Temporal Ordering of Cell Biology Diagrams
The cell cycle is a highly conserved process involving the coordinated separation of a single cell into two daughter cells. To relate transcriptional regulation across the cell cycle with oscillatory changes in protein abundance and activity, we carried out a proteome- and phospho-proteome-wide mass spectrometry profiling. Of these, 51 phosphorylation events had been previously classified as HP sensitive (sites phosphorylated less by Cdc13-HPM than Cdc13) and 50 phosphorylation events as HP insensitive (sites phosphorylated to wild-type levels by Cdc13-HPM). 7 We also confirmed that CDK substrate phosphorylation was comparable between both strains before 1-NmPP1 The cell cycle governs a precise series of molecular events, regulated by coordinated changes in protein and phosphorylation abundance, that culminates in the generation of two daughter cells.
Cell-cycle phosphorylation is temporally ordered, at least in part, through the sequential expression of different cyclins. Recent studies by Swaffer et al. and Godfrey et al. show that intrinsic properties of the substrate proteins contribute as well: good kinase substrates tend to be phosphorylated early, and good phosphatase substrates tend to be phosphorylated late. Since phosphorylation events both depend on the structural environment and influence its properties, protein structure and phosphorylation should be considered interrelated and mutually dependent. The variation of phosphorylation changes over the cell cycle scales with the structural propensities of the phosphorylated residues: from lowest Protein phosphorylation is also involved in the global control of DNA replication during the cell cycle, as well as in the mechanisms that cope with stress-induced replication blocks. Similar to eukaryotes, bacteria use Hanks-type kinases and phosphatases for signal transduction, and protein phosphorylation is involved in numerous cellular
