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

The SNF1 protein kinase is required for the regulatory response to glucose starvation in Saccharomyces cerevisiae. SNF1 is a protein serine/threonine kinase that has been widely conserved in both plants and mammals. Previously, we identified SIP1 and SIP2 as proteins that interact with SNF1 in vivo by the two-hybrid system. We have cloned the SIP2 gene and the encoded protein is homologous to SIP1 and to GAL83, which affects glucose repression of the GAL genes. We show that SIP2 and GAL83, like SIP1, co-immunoprecipitate with SNF1 and are phosphorylated in vitro. An 80 amino acid sequence, designated the ASC domain, is highly conserved at the C-termini of all three proteins. We show that this small domain can mediate protein-protein interaction with the SNF1 kinase complex. Thus, SIP1, SIP2 and GAL83 define a family of homologous proteins that are tightly associated with the SNF1 kinase, probably in alternative forms of the complex. Genetic evidence suggests that the three proteins have distinct, but related, functions in the SNF1 pathway, and deletion of GAL83 dramatically reduces SNF1 activity in immune complex assays. We propose that SIP1, SIP2 and GAL83 act as adaptors that promote the activity of SNF1 towards specific targets.
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PMID:A family of proteins containing a conserved domain that mediates interaction with the yeast SNF1 protein kinase complex. 781 28

The AMP-activated protein kinase (AMPK) in mammals, and its homologue in Saccharomyces cerevisiae, are activated by cellular stresses associated with ATP depletion. AMPK is a heterotrimer comprising a catalytic alpha subunit with associated beta and gamma subunits, these being homologous with the products of the SNF1, SIP1/SIP2/GAL83 and SNF4 genes in S. cerevisiae. The alpha subunit has at least two isoforms (alpha 1 and alpha 2), which differ in their AMP-dependence and subcellular localization, with alpha 2 complexes being partly nuclear. AMPK is activated allosterically by 5'-AMP, which also promotes phosphorylation and activation by an upstream kinase, and inhibits dephosphorylation and inactivation. Elevation of AMP always accompanies depletion of ATP due to the action of adenylate kinase. Since high ATP antagonizes the activating effects of AMP, the system behaves like a cellular 'fuel gauge'. It is activated by various types of stress associated with ATP depletion, such as hypoxia, heat shock, metabolic poisoning and, in muscle, exercise. AMPK phosphorylates multiple targets which switch off anabolic pathways and switch on alternative catabolic pathways. The yeast SNF1 complex is switched on by glucose starvation, and its targets include transcription factors that repress transcription of genes required for catabolism of alternative carbon sources.
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PMID:Roles of the AMP-activated/SNF1 protein kinase family in the response to cellular stress. 1020 18