Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Before Vicia faba root meristem cells stopped by carbohydrate starvation in principal control points (PCP1 and PCP2) start sucrose induced replication and division they go through a phase of metabolic regeneration. This interval is characterised st great sensitivity to the inhibitors of cyclin-dependent protein kinases and protein phosphatases (PPs). In the present research, changes of phosphoprotein levels in the nucleolus, nucleus and cytoplasm were analysed using okadaic acid and 6-dimethylaminopurine (6-DMAP) during the first period of cell regeneration in sucrose (0-3 h). It was established that when the cells start to leave checkpoints, the balance between protein phosphorylation and dephosphorylation shifts towards the intensified activity of PPs. Furthermore, it was also established that the structures appearing during cell regeneration, which were located around cell nuclei and which contained large amounts of phosphorylated proteins, were plastids. The reactions of protein phosphorylation which took place in the plastids were directly correlated with starch synthesis and were stopped by inactivation of protein phosphatases (PP1 and/or PP2A).
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PMID:Protein phosphorylation in Vicia faba root meristem cells during the first steps of leaving principal control points after sucrose application. 1902 74

The plant cell cycle is equipped with two principal control points: PCP1 in G1 and PCP2 in G2 phase. These checkpoints can arrest the cell cycle in response to carbohydrate starvation, while sugar presence can revive the replication and mitotic activity. The process of cell cycle revival is strongly repressed by okadaic acid (OA) or 6-dimethylaminopurine (6-DMAP), inhibitors of specific protein phosphatases 1 or 2A or kinases (cyclin-dependent kinases), respectively. In the present study, it was investigated whether inhibition of cell cycle revival is performed through interference of the above-mentioned inhibitors with the metabolic pathway of sucrose applied to the cells. Changes of hexokinase (HK) and fructokinase (FK) activities, key enzymes of hexose metabolism, were analyzed in Vicia faba root meristem cells arrested in G1 and G2 phase by carbohydrate starvation as well as in those recovered with glucose or sucrose in the presence of OA or 6-DMAP. It was shown that in the sugar-starved cells, the activity of both enzymes decreased significantly. During cell regeneration with carbohydrates, the activity of HK was induced more by sucrose than by glucose, while FK remained inactive after glucose addition. Moreover, in situ investigation of the activities of HK and FK showed that OA-induced and 6-DMAP-induced repression of the cell cycle revival is connected with the interference of these drugs in the metabolic pathway of sucrose. It was also indicated that stronger OA-induced and 6-DMAP-induced inhibition of the replication and mitosis revival, at the early stages of sucrose regeneration, was correlated with the stronger influence of these inhibitors on HK and FK activities.
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PMID:In situ activities of hexokinase and fructokinase in relation to phosphorylation status of root meristem cells of Vicia faba during reactivation from sugar starvation. 1933 47