Inhibitors such as staurosporine, H-7 or polymyxin B cannot be used in skeletal muscle to prove the role of protein kinase C on insulin action

1992 ◽  
Vol 12 (5) ◽  
pp. 413-424 ◽  
Author(s):  
Anna Gumà ◽  
Purificación Muñoz ◽  
Marta Camps ◽  
Xavier Testar ◽  
Manuel Palacín ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Insulin Action ◽  
Lactate Production ◽  
Polymyxin B ◽  
Transport Activity ◽  
System A ◽  
Kinase C

The precise role of protein kinase C in insulin action in skeletal muscle is not well defined. Based on the fact that inhibitors of protein kinase C block some insulin effects, it has been concluded that some of the biological actions of insulin are mediated via protein kinase C. In this study, we present evidence that inhibitors of protein kinase C such as staurosporine, H-7 or polymyxin B cannot be used to ascertain the role of protein kinase C in skeletal muscle. This is based on the following experimental evidences: a) staurosporine, H-7 and polymyxin B markedly block in muscle the effect of insulin on System A transport activity; however, this effect of insulin is not mimicked in muscle by TPA-induced stimulation of protein kinase C, b) H-7 and polymyxin B block insulin action on System A transport activity in an additive manner to the inhibitory effect of phorbol esters, c) staurosporine, H-7 and polymyxin B block the effect of insulin on lactate production, a process that is activated by insulin and TPA in an additive fashion, and d) staurosporine completely blocks the tyrosine kinase activity of insulin receptors partially purified from rat skeletal muscle.

scholarly journals Protein kinase C activators selectively inhibit insulin-stimulated system A transport activity in skeletal muscle at a post-receptor level

1990 ◽  
Vol 268 (3) ◽  
pp. 633-639 ◽  
Author(s):  
A Gumà ◽  
M Camps ◽  
M Palacín ◽  
X Testar ◽  
A Zorzano
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Insulin Receptor ◽  
Insulin Action ◽  
Phorbol Esters ◽  
Polymyxin B ◽  
Transport Activity ◽  
System A ◽  
Kinase C ◽  
Protein Kinase C Activation

We have investigated the role of phorbol esters on different biological effects induced by insulin in muscle, such as activation of system A transport activity, glucose utilization and insulin receptor function. System A transport activity was measured by monitoring the uptake of the system A-specific analogue alpha-(methyl)aminoisobutyric acid (MeAIB), by intact rat extensor digitorum longus muscle. The addition of 12-O-tetradecanoylphorbol 13-acetate (TPA, 0.5 microM) for 60 or 180 min did not modify basal MeAIB uptake by muscle, suggesting that insulin signalling required to stimulate MeAIB transport does not involve protein kinase C activation. However, TPA added 30 min before insulin (100 nM) markedly inhibited insulin-stimulated MeAIB uptake. The addition of polymyxin B (0.1 mM) or H-7 (1 mM), protein kinase C inhibitors, alone or in combination with TPA leads to impairment of insulin-stimulated MeAIB uptake. This paradoxical pattern is incompatible with a unique action of Polymyxin B or H-7 on protein kinase C activity. Therefore these agents are not suitable tools with which to investigate whether a certain insulin effect is mediated by protein kinase C. TPA did not cause a generalized inhibition of insulin action. Thus both TPA and insulin increased 3-O-methylglucose uptake by muscle, and their effects were not additive. Furthermore, TPA did not modify insulin-stimulated lactate production by muscle. In keeping with this selective modification of insulin action, treatment of muscles with TPA did not modify insulin receptor binding or kinase activities. In conclusion, phorbol esters do not mimic insulin action on system A transport activity; however, they markedly inhibit insulin-stimulated amino acid transport, with no modification of insulin receptor function in rat skeletal muscle. It is suggested that protein kinase C activation causes a selective post-receptor modification on the biochemical pathway by which insulin activates system A amino acid transport in muscle.

scholarly journals Interplay and Effects of Temporal Changes in the Phosphorylation State of Serine-302, -307, and -318 of Insulin Receptor Substrate-1 on Insulin Action in Skeletal Muscle Cells

2008 ◽  
Vol 22 (12) ◽  
pp. 2729-2740 ◽  
Author(s):  
Cora Weigert ◽  
Matthias Kron ◽  
Hubert Kalbacher ◽  
Ann Kathrin Pohl ◽  
Heike Runge ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Insulin Receptor ◽  
Insulin Action ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Insulin Signal ◽  
Kinase C ◽  
Phosphorylation Pattern

Abstract Transduction of the insulin signal is mediated by multisite Tyr and Ser/Thr phosphorylation of the insulin receptor substrates (IRSs). Previous studies on the function of single-site phosphorylation, particularly phosphorylation of Ser-302, -307, and -318 of IRS-1, showed attenuating as well as enhancing effects on insulin action. In this study we investigated a possible cross talk of these opposedly acting serine residues in insulin-stimulated skeletal muscle cells by monitoring phosphorylation kinetics, and applying loss of function, gain of function, and combination mutants of IRS-1. The phosphorylation at Ser-302 was rapid and transient, followed first by Ser-318 phosphorylation and later by phosphorylation of Ser-307, which remained elevated for 120 min. Mutation of Ser-302 to alanine clearly reduced the subsequent protein kinase C-ζ-mediated Ser-318 phosphorylation. The Ser-307 phosphorylation was independent of Ser-302 and/or Ser-318 phosphorylation status. The functional consequences of these phosphorylation patterns were studied by the expression of IRS-1 mutants. The E302A307E318 mutant simulating the early phosphorylation pattern resulted in a significant increase in Akt and glycogen synthase kinase 3 phosphorylation. Furthermore, glucose uptake was enhanced. Because the down-regulation of the insulin signal was not affected, this phosphorylation pattern seems to be involved in the enhancement but not in the termination of the insulin signal. This enhancing effect was completely absent when Ser-302 was unphosphorylated and Ser-307 was phosphorylated as simulated by the A302E307E318 mutant. Phospho-Ser-318, sequentially phosphorylated at least by protein kinase C-ζ and a mammalian target of rapamycin/raptor-dependent kinase, was part of the positive as well as of the subsequent negative phosphorylation pattern. Thus we conclude that insulin stimulation temporally generates different phosphorylation statuses of the same residues that exert different functions in insulin signaling.

The role of protein kinase C in LHRH-induced LH and FSH release and LHRH self-priming in rat anterior pituitary glands in vitro

1988 ◽  
Vol 116 (2) ◽  
pp. 231-239 ◽  
Author(s):  
M. S. Johnson ◽  
R. Mitchell ◽  
G. Fink
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phorbol Esters ◽  
Polymyxin B ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Kinase C ◽  
Pituitary Glands

ABSTRACT We have investigated the role of protein kinase C (PKC) in LHRH-induced LH and FSH secretion and LHRH priming. Hemipituitary glands from pro-oestrous rats were incubated with agents known to affect PKC and with or without LHRH, during which time the secretion of gonadotrophins was measured. Phorbol esters and phospholipase C, activators of PKC, released LH and FSH in a concentration-dependent manner and potentiated the LHRH-induced secretion of gonadotrophins in parallel with their ability to release these hormones alone. Inhibitors of PKC had either no effect on LH release (1-(5-isoquinolinesulphonyl)-2-methylpiperazine hydrochloride) or they augmented LHRH-induced gonadotrophin release (polymyxin B and 8-(N,N-diethylamino) octyl-3,4,5-trimethoxybenzoate). Neither the activators nor the inhibitors of PKC, when present with LHRH, caused any change in LHRH priming, even though the activators alone produced a release of gonadotrophins that showed a temporal pattern similar to that produced by LHRH priming. The profiles of effects on LH and FSH secretion were always qualitatively similar. These results show that PKC may be involved in general regulation of gonadotrophin release but that it is not important in acute responses to LHRH nor in LHRH self-priming. J. Endocr. (1988) 116, 231–239

scholarly journals Phosphorylation of Ser357of Rat Insulin Receptor Substrate-1 Mediates Adverse Effects of Protein Kinase C-δ on Insulin Action in Skeletal Muscle Cells

2008 ◽  
Vol 283 (17) ◽  
pp. 11226-11233 ◽  
Author(s):  
Rizwana Sanaullah Waraich ◽  
Cora Weigert ◽  
Hubert Kalbacher ◽  
Anita M. Hennige ◽  
Stefan Z. Lutz ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Adverse Effects ◽  
Insulin Receptor ◽  
Insulin Action ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Insulin Receptor Substrate ◽  
Kinase C

The role of protein kinase C in insulin action

1992 ◽  
Vol 4 (2) ◽  
pp. 133-143 ◽  
Author(s):  
Robert V. Farese ◽  
Mary L. Standaert ◽  
Thomas Arnold ◽  
Bingzhi Yu ◽  
Tatsuo Ishizuka ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Insulin Action ◽  
Kinase C

Regulation of human monocarboxylate transporter 4 in skeletal muscle cells: The role of protein kinase C (PKC)

2012 ◽  
Vol 428 (1-2) ◽  
pp. 25-32 ◽  
Author(s):  
Katsuya Narumi ◽  
Masaki Kobayashi ◽  
Sho Otake ◽  
Ayako Furugen ◽  
Natsuko Takahashi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Monocarboxylate Transporter ◽  
Kinase C ◽  
Monocarboxylate Transporter 4
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