PMID:20701589

Citation	Vichaiwong, K, Purohit, S, An, D, Toyoda, T, Jessen, N, Hirshman, MF and Goodyear, LJ (2010) Contraction regulates site-specific phosphorylation of TBC1D1 in skeletal muscle. Biochem. J. 431:311-20
Abstract	TBC1D1 (tre-2/USP6, BUB2, cdc16 domain family member 1) is a Rab-GAP (GTPase-activating protein) that is highly expressed in skeletal muscle, but little is known about TBC1D1 regulation and function. We studied TBC1D1 phosphorylation on three predicted AMPK (AMP-activated protein kinase) phosphorylation sites (Ser231, Ser660 and Ser700) and one predicted Akt phosphorylation site (Thr590) in control mice, AMPKα2 inactive transgenic mice (AMPKα2i TG) and Akt2-knockout mice (Akt2 KO). Muscle contraction significantly increased TBC1D1 phosphorylation on Ser231 and Ser660, tended to increase Ser700 phosphorylation, but had no effect on Thr590. AICAR (5-aminoimidazole-4-carboxyamide ribonucleoside) also increased phosphorylation on Ser231, Ser660 and Ser700, but not Thr590, whereas insulin only increased Thr590 phosphorylation. Basal and contraction-stimulated TBC1D1 Ser231, Ser660 and Ser700 phosphorylation were greatly reduced in AMPKα2i TG mice, although contraction still elicited a small increase in phosphorylation. Akt2 KO mice had blunted insulin-stimulated TBC1D1 Thr590 phosphorylation. Contraction-stimulated TBC1D1 Ser231 and Ser660 phosphorylation were normal in high-fat-fed mice. Glucose uptake in vivo was significantly decreased in tibialis anterior muscles overexpressing TBC1D1 mutated on four predicted AMPK phosphorylation sites. In conclusion, contraction causes site-specific phosphorylation of TBC1D1 in skeletal muscle, and TBC1D1 phosphorylation on AMPK sites regulates contraction-stimulated glucose uptake. AMPK and Akt regulate TBC1D1 phosphorylation, but there must be additional upstream kinases that mediate TBC1D1 phosphorylation in skeletal muscle.
Links	PubMed PMC2947193 Online version:10.1042/BJ20101100
Keywords	AMP-Activated Protein Kinases/metabolism; Aminoimidazole Carboxamide/analogs & derivatives; Aminoimidazole Carboxamide/pharmacology; Animals; Antibodies, Phospho-Specific/pharmacology; Consensus Sequence; Dietary Fats/pharmacology; GTPase-Activating Proteins; Glucose/metabolism; In Vitro Techniques; Insulin/pharmacology; Mice; Muscle Contraction/drug effects; Muscle Contraction/physiology; Muscle, Skeletal/drug effects; Muscle, Skeletal/enzymology; Muscle, Skeletal/physiology; Mutant Proteins/metabolism; Mutation/genetics; Nuclear Proteins/genetics; Nuclear Proteins/metabolism; Phosphorylation/drug effects; Phosphoserine/metabolism; Proto-Oncogene Proteins c-akt/metabolism; Ribonucleotides/pharmacology
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
MOUSE:AAPK2	enables	GO:0004674: protein serine/threonine kinase activity	ECO:0000269: experimental evidence used in manual assertion		F		Seeded From UniProt	complete

References

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