| First Author | Jensen TE | Year | 2009 |
| Journal | Am J Physiol Endocrinol Metab | Volume | 297 |
| Issue | 2 | Pages | E340-8 |
| PubMed ID | 19458061 | Mgi Jnum | J:151246 |
| Mgi Id | MGI:4353455 | Doi | 10.1152/ajpendo.90610.2008 |
| Citation | Jensen TE, et al. (2009) Knockout of the predominant conventional PKC isoform, PKCalpha, in mouse skeletal muscle does not affect contraction-stimulated glucose uptake. Am J Physiol Endocrinol Metab 297(2):E340-8 |
| abstractText | Conventional (c) protein kinase C (PKC) activity has been shown to increase with skeletal muscle contraction, and numerous studies using primarily pharmacological inhibitors have implicated cPKCs in contraction-stimulated glucose uptake. Here, to confirm that cPKC activity is required for contraction-stimulated glucose uptake in mouse muscles, contraction-stimulated glucose uptake ex vivo was first evaluated in the presence of three commonly used cPKC inhibitors (calphostin C, Go-6976, and Go-6983) in incubated mouse soleus and extensor digitorum longus (EDL) muscles. All potently inhibited contraction-stimulated glucose uptake by 50-100%, whereas both Go compounds, but not calphostin C, inhibited insulin-stimulated glucose uptake modestly. AMP-activated protein kinase (AMPK) and eukaryotic elongation factor 2 phosphorylation was unaffected by the blockers. PKCalpha was estimated to account for approximately 97% of total cPKC protein expression in skeletal muscle. However, in muscles from PKCalpha knockout (KO) mice, neither contraction- nor phorbol ester-stimulated glucose uptake ex vivo differed compared with the wild type. Furthermore, the effects of calphostin C and Go-6983 on contraction-induced glucose uptake were similar in muscles lacking PKCalpha and in the wild type. It can be concluded that PKCalpha, representing approximately 97% of cPKC in skeletal muscle, is not required for contraction-stimulated glucose uptake. Thus the effect of the PKC blockers on glucose uptake is either nonspecific working on other parts of contraction-induced signaling or the remaining cPKC isoforms are sufficient for stimulating glucose uptake during contractions. |
