Na,K-ATPase activity in mouse muscle is regulated by AMPK and PGC-1a

TY - JOUR

T1 - Na,K-ATPase activity in mouse muscle is regulated by AMPK and PGC-1a

AU - Ingwersen, Maria S

AU - Kristensen, Michael

AU - Pilegaard, Henriette

AU - Wojtaszewski, Jørgen

AU - Richter, Erik

AU - Juel, Carsten

N1 - CURIS 2011 5200 066

PY - 2011/7

Y1 - 2011/7

N2 - Na,K-ATPase activity, which is crucial for skeletal muscle function, undergoes acute and long-term regulation in response to muscle activity. The aim of the present study was to test the hypothesis that AMP kinase (AMPK) and the transcriptional coactivator PGC-1α are underlying factors in long-term regulation of Na,K-ATPase isoform (α,β and PLM) abundance and Na + affinity. Repeated treatment of mice with the AMPK activator AICAR decreased total PLM protein content but increased PLM phosphorylation, whereas the number of α- and β-subunits remained unchanged. The K m for Na + stimulation of Na,K-ATPase was reduced (higher affinity) after AICAR treatment. PLM abundance was increased in AMPK kinase-dead mice compared with control mice, but PLM phosphorylation and Na,K-ATPase Na + affinity remained unchanged. Na,K-ATPase activity and subunit distribution were also measured in mice with different degrees of PGC-1α expression. Protein abundances of α1 and α2 were reduced in PGC-1α +/- and -/- mice, and the β 1/β 2 ratio was increased with PGC-1α overexpression (TG mice). PLM protein abundance was decreased in TG mice, but phosphorylation status was unchanged. Na,K-ATPase V max was decreased in PCG-1α TG and KO mice. Experimentally in vitro induced phosphorylation of PLM increased Na,K-ATPase Na + affinity, confirming that PLM phosphorylation is important for Na,K-ATPase function. In conclusion, both AMPK and PGC-1α regulate PLM abundance, AMPK regulates PLM phosphorylation and PGC-1α expression influences Na,K-ATPase α 1 and α 2 content and β 1/β 2 isoform ratio. Phosphorylation of the Na,K-ATPase subunit PLM is an important regulatory mechanism.

AB - Na,K-ATPase activity, which is crucial for skeletal muscle function, undergoes acute and long-term regulation in response to muscle activity. The aim of the present study was to test the hypothesis that AMP kinase (AMPK) and the transcriptional coactivator PGC-1α are underlying factors in long-term regulation of Na,K-ATPase isoform (α,β and PLM) abundance and Na + affinity. Repeated treatment of mice with the AMPK activator AICAR decreased total PLM protein content but increased PLM phosphorylation, whereas the number of α- and β-subunits remained unchanged. The K m for Na + stimulation of Na,K-ATPase was reduced (higher affinity) after AICAR treatment. PLM abundance was increased in AMPK kinase-dead mice compared with control mice, but PLM phosphorylation and Na,K-ATPase Na + affinity remained unchanged. Na,K-ATPase activity and subunit distribution were also measured in mice with different degrees of PGC-1α expression. Protein abundances of α1 and α2 were reduced in PGC-1α +/- and -/- mice, and the β 1/β 2 ratio was increased with PGC-1α overexpression (TG mice). PLM protein abundance was decreased in TG mice, but phosphorylation status was unchanged. Na,K-ATPase V max was decreased in PCG-1α TG and KO mice. Experimentally in vitro induced phosphorylation of PLM increased Na,K-ATPase Na + affinity, confirming that PLM phosphorylation is important for Na,K-ATPase function. In conclusion, both AMPK and PGC-1α regulate PLM abundance, AMPK regulates PLM phosphorylation and PGC-1α expression influences Na,K-ATPase α 1 and α 2 content and β 1/β 2 isoform ratio. Phosphorylation of the Na,K-ATPase subunit PLM is an important regulatory mechanism.

U2 - 10.1007/s00232-011-9365-7

DO - 10.1007/s00232-011-9365-7

M3 - Journal article

C2 - 21687978

SN - 1432-1424

VL - 242

SP - 1

EP - 10

JO - The Journal of Membrane Biology

JF - The Journal of Membrane Biology

IS - 1

ER -