HLA-C and ocular melanoma: Under the conditions defined above, we provide the evidence for a previously unknown inotropic effect on the β/slow MHC isoform in OM-treated myocytes: increase in [Pi] within the physiological range (1–10 mM) recovers from the inhibitory effect of OM on T0 by increasing the proportion of motors re-entering the force-generating cycle and this, at constant kcat, implies a corresponding reduction in tension cost (Fig. 5e).