The Inhibitory Effect of Phospholemman on the Sodium Pump Requires Its Palmitoylation

Abstract

Background: Phospholemman regulates the plasmalemmal sodium pump in excitable tissues such as the heart. Results: Phospholemman is palmitoylated at two intracellular cysteines, and this reduces ion transport by the sodium pump. Conclusion: Phospholemman must be palmitoylated to inhibit the sodium pump. Significance: This is a potentially new way to regulate the sodium pump, an enzyme expressed in most eukaryotic cells.

S-Palmitoylation and S-Oleoylation of Rabbit and Pig Sarcolipin

“…ber of the FXYD family (49) and somewhat analogous to SLN, inhibits the Na ϩ ,K ϩ -ATPase in a palmitoylation-dependent fashion (35). In our hands, depalmitoylation through hydroxylamine treatment performed on SR membranes led to an increase of the Ca 2ϩ -ATPase activity in SR vesicles of 30% for rabbit, slightly more than for the rat (20%, Fig.…”

A Separate Pool of Cardiac Phospholemman That Does Not Regulate or Associate with the Sodium Pump

“…The anti-clathrin heavy chain and anti-PP2A catalytic subunit were from BD Biosciences. All other antibodies were as previously described (27). Unless indicated otherwise, all reagents were obtained from Sigma and were of the highest grade available.…”

“…Biotinylation and Purification of Cell Surface Proteins-Cell surface proteins were prepared from ARVMs that had been plated on laminin-coated multiwell dishes using a protocol identical to that previously described for immortalized cell lines (27).…”

Essential role of flotillin-1 palmitoylation in the intracellular localization and signaling function of IGF-1 receptor

“…Purification of palmitoylated proteins by the fatty acyl biotin exchange was performed as described previously Tulloch et al, 2011). HEK293T and HeLa cells were lysed with buffer A (1% SDS in PBS containing 0.2 mM PMSF, 1 μg/μl aprotinin and 1 μg/μl leupeptin) and free cysteine residues were alkylated by overnight incubation at 4°C with 25 mg/ml N-ethylmaleimide.…”