@entity1 @entity860 -activated protein kinase (AMPK) is the downstream component of a cascade that is activated by cellular stresses associated with @entity855 depletion. AMPK exists as heterotrimeric alphabetagamma complexes, where the catalytic subunit has two isoforms ( @entity6927 ) with different tissue distributions. The budding @entity375 homologue is the SNF1 kinase complex, which is essential for derepression of @entity413 -repressed genes, and seems to act by the direct phosphorylation of transcription factors in the nucleus. AMPK complexes containing the alpha2 rather than the @entity6927 isoform have a greater dependence on @entity860 (approx. 5-fold stimulation compared with approx. 2-fold) both in direct allosteric activation and in reactivation by the upstream kinase. We have also examined their subcellular localization by using Western blotting of nuclear preparations, and by using two detection methods in the confocal microscope, i.e. indirect immunofluorescence of endogenous proteins and transfection of DNA species encoding green fluorescent protein-alpha-subunit fusions. By all three methods a significant proportion of alpha2, but not @entity6927 , is localized in the nucleus. Like SNF1, @entity33725 complexes could therefore be involved in the direct regulation of gene expression. The observed differences in the regulation of @entity6927 complexes by @entity860 might result in differential responses to @entity855 depletion in distinct cellular and subcellular locations.

XXXX -activated protein kinase: greater @entity860 dependence, and preferential nuclear localization, of complexes containing the alpha2 isoform.

@entity1 :: ('9606', 'Species') :: ['Mammalian'] @entity855 :: ('MESH:D000255', 'Chemical') :: ['ATP'] @entity33725 :: ('5563', 'Gene') :: ['AMPK-alpha2'] @entity860 :: ('MESH:D000249', 'Chemical') :: ['AMP'] @entity375 :: ('4932', 'Species') :: ['yeast'] @entity413 :: ('MESH:D005947', 'Chemical') :: ['glucose'] @entity6927 :: ('146', 'Gene') :: ['alpha1', 'alpha1 and alpha2']
@entity860 :: (MESH:D000249,Chemical) :: ['AMP']
