Defining the contribution of AMP-activated protein kinase (AMPK) and protein kinase C (PKC) in regulation of glucose uptake by metformin in skeletal muscle cells. / Turban, S.; Stretton, C.; Drouin, O.; Green, C.J.; Watson, M.L.; Gray, A.; Ross, F.; Lantier, L.; Viollet, B.; Hardie, D.G.; Hundal, H.S.; Marette, A.
In: Journal of Biological Chemistry, Vol. 287, No. 24, 08.06.2012, p. 20088-20099.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Defining the contribution of AMP-activated protein kinase (AMPK) and protein kinase C (PKC) in regulation of glucose uptake by metformin in skeletal muscle cells
A1 - Turban,S.
A1 - Stretton,C.
A1 - Drouin,O.
A1 - Green,C.J.
A1 - Watson,M.L.
A1 - Gray,A.
A1 - Ross,F.
A1 - Lantier,L.
A1 - Viollet,B.
A1 - Hardie,D.G.
A1 - Hundal,H.S.
A1 - Marette,A.
AU - Turban,S.
AU - Stretton,C.
AU - Drouin,O.
AU - Green,C.J.
AU - Watson,M.L.
AU - Gray,A.
AU - Ross,F.
AU - Lantier,L.
AU - Viollet,B.
AU - Hardie,D.G.
AU - Hundal,H.S.
AU - Marette,A.
PY - 2012/6/8
Y1 - 2012/6/8
N2 - The importance of AMP-activated protein kinase (AMPK) and protein kinase C (PKC) as effectors of metformin (Met) action on glucose uptake (GU) in skeletal muscle cells was investigated. GUin L6 myotubes was stimulated 2-fold following 16 h of Met treatment and acutely enhanced by insulin in an additive fashion. Insulin-stimulatedGUwas sensitive to PI3K inhibition, whereas that induced by Met was not. Met and its related biguanide, phenformin, stimulated AMPK activation/phosphorylation to a level comparable with that induced by the AMPK activator, 5-amino-1-ß-D-ribofuranosyl-imidazole-4-carboxamide (AICAR). However, the increase in GU elicited by AICAR was significantly lower than that induced by either biguanide. Expression of a constitutively active AMPK mimicked the effects of AICAR on GU, whereas a dominant interferingAMPK or shRNA silencing of AMPK prevented AICAR-stimulated GU and Met-induced AMPK signaling but only repressed biguanide- stimulated GU by ~20%. Consistent with this, analysis of GU in muscle cells from a1 /a2 AMPK-deficient mice revealed a significant retention of Met-stimulated GU, being reduced by ~35% compared with that of wild type cells. Atypical PKCs (aPKCs) have been implicated in Met-stimulated GU, and in line with this, Met and phenformin induced activation/phosphorylation of aPKC in L6 myotubes. However, although cellular depletion of aPKC (>90%) led to loss in biguanide-induced aPKC phosphorylation, it had no effect on Met-stimulated GU, whereas inhibitors targeting novel/conventional PKCs caused a significant reduction in biguanide-induced GU. Our findings indicate that although Met activates AMPK, a significant component of Met-stimulated GU in muscle cells is mediated via an AMPK-independent mechanism that involves novel/conventional PKCs. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc.
AB - The importance of AMP-activated protein kinase (AMPK) and protein kinase C (PKC) as effectors of metformin (Met) action on glucose uptake (GU) in skeletal muscle cells was investigated. GUin L6 myotubes was stimulated 2-fold following 16 h of Met treatment and acutely enhanced by insulin in an additive fashion. Insulin-stimulatedGUwas sensitive to PI3K inhibition, whereas that induced by Met was not. Met and its related biguanide, phenformin, stimulated AMPK activation/phosphorylation to a level comparable with that induced by the AMPK activator, 5-amino-1-ß-D-ribofuranosyl-imidazole-4-carboxamide (AICAR). However, the increase in GU elicited by AICAR was significantly lower than that induced by either biguanide. Expression of a constitutively active AMPK mimicked the effects of AICAR on GU, whereas a dominant interferingAMPK or shRNA silencing of AMPK prevented AICAR-stimulated GU and Met-induced AMPK signaling but only repressed biguanide- stimulated GU by ~20%. Consistent with this, analysis of GU in muscle cells from a1 /a2 AMPK-deficient mice revealed a significant retention of Met-stimulated GU, being reduced by ~35% compared with that of wild type cells. Atypical PKCs (aPKCs) have been implicated in Met-stimulated GU, and in line with this, Met and phenformin induced activation/phosphorylation of aPKC in L6 myotubes. However, although cellular depletion of aPKC (>90%) led to loss in biguanide-induced aPKC phosphorylation, it had no effect on Met-stimulated GU, whereas inhibitors targeting novel/conventional PKCs caused a significant reduction in biguanide-induced GU. Our findings indicate that although Met activates AMPK, a significant component of Met-stimulated GU in muscle cells is mediated via an AMPK-independent mechanism that involves novel/conventional PKCs. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc.
UR - http://www.scopus.com/inward/record.url?partnerID=yv4JPVwI&eid=2-s2.0-84862001123&md5=c9b5c75e0fd59cee8ef45a027060e859
U2 - 10.1074/jbc.M111.330746
DO - 10.1074/jbc.M111.330746
M1 - Article
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 24
VL - 287
SP - 20088
EP - 20099
ER -