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The α1 and α2 isoforms of the AMP‐activated protein kinase have similar activities in rat liver but exhibit differences in substrate specificity in vitro
Author(s) -
Woods Angela,
Salt Ian,
Scott James,
Hardie D.Grahame,
Carling David
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(96)01209-4
Subject(s) - heterotrimeric g protein , gene isoform , protein subunit , ampk , protein kinase a , substrate (aquarium) , amp activated protein kinase , in vitro , biochemistry , kinase , chemistry , microbiology and biotechnology , peptide , biology , signal transduction , g protein , gene , ecology
The AMP‐activated protein kinase (AMPK) is a heterotrimeric complex composed of a catalytic subunit (a) and two regulatory subunits (β and γ). Two isoforms of the catalytic subunit (αl and (α2) have been identified. We show here that the αl‐ and α2‐containing complexes contribute approximately equally to total AMPK activity in rat liver. Furthermore, expression of al or a2 with β and Y in mammalian cells demonstrates that both complexes have equal specific activity measured with the SAMS peptide. Using variant peptides, however, we show that al and a2 exhibit slightly different substrate preferences, which suggest that the two isoforms could play different physiological roles within the cell.