Table 1.
Characteristics of skeletal muscle nitric oxide synthase (NOS) isoforms [37, 42, 44, 50, 54, 64, 65]
| nNOS variants | eNOS | iNOS | |
|---|---|---|---|
| Localization | Sarcolemma (nNOSμ) | Plasma caveoli of ECs | Sarcolemma |
| Sarcoplasm (nNOSμ) | Mt | ||
| Golgi apparatus (nNOSβ) | |||
| Mt (nNOSα) | |||
| Co-localized molecules | α1-syn (sarcolemmal nNOSμ) | Cav-1 | Cav-3 |
| SR, RyR1 (sarcoplasmic nNOSμ) | Mt-complex II | ||
| sGC, PKG (nNOSβ) | |||
| PGC1α, Mt-complex I, IV (nNOSα)` | |||
| Up-regulators | Hypoxia, crush injury, contraction, myotube fusion | Hypoxia, contraction, HSP | Cytokines, myotube fusion |
| Inhibitors | Cav-3, PIN protein | Cav-1 | Kalirin, Cav-3 |
| Post-translational modification | Phosphorylation, nitrosylation | Phosphorylation, nitrosylation, myristoylation, palmitoylation | Phosphorylation, nitrosylation |
α1-syn, α1-syntrophin; Cav; caveolin; ECs, endothelial cells; eNOS, endothelial nitric oxide synthase; HSP, heat shock protein; iNOS; inducible nitric oxide synthase; Mt, mitochondria; nNOS, neuronal nitric oxide synthase; PIN, protein inhibitor of nitric oxide synthase; PGC-1α, peroxisome proliferator activated receptor-γ co-activator 1α; PKG, protein kinase G; RyR1; ryanodine receptor 1 Ca2+ release channel; sGC; soluble guanylate cyclase; SR, sarcoplasmic reticulum