Sarcolipin alters SERCA1a interdomain communication by impairing binding of both calcium and ATP

Cédric Montigny,Ji-Shen Zheng,Marc Le Maire,Dong Liang Huang,Veronica Beswick,Christine Jaxel,Thomas Barbot,Nadège Jamin

doi:10.1038/s41598-021-81061-6

Abstract

Sarcolipin (SLN), a single-spanning membrane protein, is a regulator of the sarco-endoplasmic reticulum Ca2+-ATPase (SERCA1a). Chemically synthesized SLN, palmitoylated or not (pSLN or SLN), and recombinant wild-type rabbit SERCA1a expressed in S. cerevisiae design experimental conditions that provide a deeper understanding of the functional role of SLN on the regulation of SERCA1a. Our data show that chemically synthesized SLN interacts with recombinant SERCA1a, with calcium-deprived E2 state as well as with calcium-bound E1 state. This interaction hampers the binding of calcium in agreement with published data. Unexpectedly, SLN has also an allosteric effect on SERCA1a transport activity by impairing the binding of ATP. Our results reveal that SLN significantly slows down the E2 to Ca2.E1 transition of SERCA1a while it affects neither phosphorylation nor dephosphorylation. Comparison with chemically synthesized SLN deprived of acylation demonstrates that palmitoylation is not necessary for either inhibition or association with SERCA1a. However, it has a small but statistically significant effect on SERCA1a phosphorylation when various ratios of SLN-SERCA1a or pSLN-SERCA1a are tested.

Highlights

Sarcolipin (SLN), a single-spanning membrane protein, is a regulator of the sarco-endoplasmic reticulum Ca2+-ATPase (SERCA1a)
Our data show that chemically synthesized SLN interacts with recombinant SERCA1a, with calcium-deprived E2 state as well as with calcium-bound E1 state
Our results reveal that SLN significantly slows down the E2 to Ca2.E1 transition of SERCA1a while it affects neither phosphorylation nor dephosphorylation

Summary

Introduction

Sarcolipin (SLN), a single-spanning membrane protein, is a regulator of the sarco-endoplasmic reticulum Ca2+-ATPase (SERCA1a). Our data show that chemically synthesized SLN interacts with recombinant SERCA1a, with calciumdeprived E2 state as well as with calcium-bound E1 state. Comparison with chemically synthesized SLN deprived of acylation demonstrates that palmitoylation is not necessary for either inhibition or association with SERCA1a. It has a small but statistically significant effect on SERCA1a phosphorylation when various ratios of SLNSERCA1a or pSLN-SERCA1a are tested. The sarco-endoplasmic reticulum C a2+-ATPase (SERCA1a) is a 110 kDa integral membrane transporter and is one of the major actor of calcium homeostasis in fast-twitch muscle.

Methods

Results

Conclusion