title: Characterization of the liver kinase B1-mouse protein-25 -Ste-20-related adaptor protein complex in adult mouse skeletal muscle.
abstract: In liver, the AMP-activated protein kinase kinase (AMPKK) complex was identified as the association of liver kinase B1 (LKB1), mouse protein 25 (MO25α/β), and Ste-20-related adaptor protein (STRADα/β); however, this complex has yet to be characterized in skeletal muscle. We demonstrate the expression of the LKB1-MO25-STRAD complex in skeletal muscle, confirm the absence of mRNA splice variants, and report the relative mRNA expression levels of these proteins in control and muscle-specific LKB1 knockout (LKB1(-/-)) mouse muscle. LKB1 detection in untreated control and LKB1(-/-) muscle lysates revealed two protein bands (50 and 60 kDa), although only the heavier band was diminished in LKB1(-/-) samples [55 ± 2.5 and 13 ± 1.5 arbitrary units (AU) in control and LKB1(-/-), respectively, P < 0.01], suggesting that LKB1 is not represented at 50 kDa, as previously cited. The 60-kDa LKB1 band was further confirmed following purification using polyethylene glycol (43 ± 5 and 8.4 ± 4 AU in control and LKB1(-/-), respectively, P < 0.01) and ion-exchange fast protein liquid chromatography. Mass spectrometry confirmed LKB1 protein detection in the 60-kDa protein band, while none was detected in the 50-kDa band. Coimmunoprecipitation assays demonstrated LKB1-MO25-STRAD complex formation. Quantitative PCR revealed significantly reduced LKB1, MO25α, and STRADβ mRNA in LKB1(-/-) muscle. These findings demonstrate that the LKB1-MO25-STRAD complex is the principal AMPKK in skeletal muscle.
authors: Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, USA.
authors: Cody D
authors: CD
authors: Smith
authors: Richard A
authors: RA
authors: Compton
authors: Joshua S
authors: JS
authors: Bowler
authors: Jonathan T
authors: JT
authors: Kemp
authors: Sterling N
authors: SN
authors: Sudweeks
authors: David M
authors: DM
authors: Thomson
authors: William W
authors: WW
authors: Winder
mesh_terms: D000091162:AMP-Activated Protein Kinase Kinases; D055372:AMP-Activated Protein Kinases; D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D033942:Adaptor Proteins, Vesicular Transport / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002135:Calcium-Binding Proteins; D005260:Female; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014018:Tissue Distribution
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; C000629659:Cab39 protein, mouse; D002135:Calcium-Binding Proteins; D009097:Multienzyme Complexes; D046912:Multiprotein Complexes; D012333:RNA, Messenger; C518004:STRAD protein, mouse; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; C491654:Stk11 protein, mouse; D000091162:AMP-Activated Protein Kinase Kinases; D055372:AMP-Activated Protein Kinases