Regulation of fast skeletal muscle activity by SERCA1 vicinal-cysteines

Abstract

During prolonged skeletal muscle contractions free radicals are produced that may lead to fatigue. Vicinal cysteines, known as a Vicinal-thiol groups react preferentially among them depending on redox potential. Therefore, we examined the role of VT groups on the activity and conformational changes of sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA1) from rabbit skeletal muscle isolated SR, by selective oxidation-reduction of VT-groups. After Ca(2+) is released from the SR to start contraction, SERCA1 pumps this cytosolic Ca(2+) back to the SR leading to muscle relaxation. Phenylarsine oxide (PAO) reacts selectively with VT-proteins forming dithioarsines, which are stable but exchanges rapidly with 2,3-dimercaptopropanol (BAL). When 0.1 mM PAO is added to isolated SR, 60 and 67% inhibition of SERCA1 hydrolytic and Ca(2+) uptake activities, respectively is observed. ATPase activity was fully reversible with 1 mM BAL. The SERCA1 thermal inactivation determined from isolated SR from muscle at rest showed a single transition for inactivation (T(i)) at 49 +/- 1.12 degrees C. In the presence of 0.1 mM PAO, SERCA1 shows two transitions at T(i) 34 +/-0.9 degrees C and at 27 +/-1.2 degrees C. The thermal denaturation profile of SERCA1 from muscle at rest, showed two transitions at T(m) = 51.5 +/-1.3 degrees C and 63 +/-1.02 degrees C related to nucleotide and Ca(2+) binding domains, respectively. Whereas isolated SR obtained after a protocol of tetanic stimulation to produce muscle fatigue, showed three transitions in the SERCA1 denaturation profile similar to the effect of PAO, addition of 1 mM BAL reverted the effect of fatigue on SERCA1 denaturation profile. These results indicate a mechanism relating VT group's oxidation to muscle fatigue.

Cholesterol Depletion Uncouples �-dystroglycans from Discrete Sarcolemmal Domains, Reducing the Mechanical Activity of Skeletal Muscle

“…Because MβCD is not membrane-permeable, the effect observed on the muscle force is related to the reduction of the cholesterol concentration in surface membranes. During tetanic contraction, the SR is depleted of calcium and does not have time to recover due to the reduced activity of the SR calcium pump (SERCA1), which leads to muscle fatigue [50]. Based on the results shown in Fig.…”

Dietary α‐tocopherol and neuromuscular health: Search for optimal dose and molecular mechanisms continues!

“…Dysregulated calcium homeostasis through free radical‐mediated oxidation of thiols has been implicated in muscle fatigue 50. Oxidation of vicinal (adjacent) cysteines of sarcoplasmic reticulum Ca(2+)‐ATPase (SERCA1) under conditions that simulate titanic stimulation induced muscle fatigue has also been suggested 75.…”

Altered calcium pump and secondary deficiency of γ-sarcoglycan and microspan in sarcoplasmic reticulum membranes isolated from δ-sarcoglycan knockout mice

“…Transition A corresponded to the denaturation of the nucleotide-binding domain (NBD), and transition B corresponded to the denaturation of the transmembrane Ca 2+ -binding domain (CBD) [21,24]. Several pieces of evidence demonstrated that conformational changes in SERCA1 induced by the presence of SERCA1 inhibitors such as the calcium channel blocker D-600 [24] or redox modification through SERCA1 vicinal thiol oxidation [25] and biological conditions that modify SERCA1 activity such as changes during muscle fatigue or muscle adaptation to exercise [25,26] are reflected by changes in the SERCA1 conformations revealed by modification on the SERCA1 thermodynamic parameters obtained from thermal denaturation (DSC). Fig.…”