AKAP6 and phospholamban colocalize and interact in HEK-293T cells and primary murine cardiomyocytes.

Phospholamban (PLN) is an important Ca modulator at the sarcoplasmic reticulum (SR) of striated muscles. It physically interacts and inhibits sarcoplasmic reticulum Ca ATPase (SERCA2) function, whereas a protein kinase A (PKA)-dependent phosphorylation at its serine 16 reverses the inhibition. The underlying mechanism of this post-translational modification, however, remains not fully understood.

Diaphragm assessment in mice overexpressing phospholamban in slow-twitch type I muscle fibers.

Aims: Phospholamban (PLN) and sarcolipin (SLN) are small inhibitory proteins that regulate the sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) pump. Previous work from our laboratory revealed that in the soleus and gluteus minimus muscles of mice overexpressing PLN (Pln (OE)), SERCA function was impaired, dynamin 2 (3-5 fold) and SLN (7-9 fold) were upregulated, and features of human centronuclear myopathy (CNM) were observed. Here, we performed structural and functional experiments to evaluate whether the diaphragm muscles of the Pln (OE) mouse would exhibit CNM pathology and muscle weakness.

ATP consumption by sarcoplasmic reticulum Ca2+ pumps accounts for 50% of resting metabolic rate in mouse fast and slow twitch skeletal muscle.

In this study, we aimed to directly quantify the relative contribution of Ca(2+) cycling to resting metabolic rate in mouse fast-twitch (extensor digitorum longus, EDL) and slow-twitch (soleus) skeletal muscle. Resting oxygen consumption of isolated muscles (Vo(2), microl.g wet wt(-1).