A kink in DWORF helical structure controls the activation of the sarcoplasmic reticulum Ca2+-ATPase

U. Venkateswara Reddy, Daniel K Weber, Songlin Wang, Erik Larsen, Alfonso De Simone, Gopinath Tata, Seth Robia, Gianluigi Veglia

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

SERCA is a P-type ATPase embedded in the sarcoplasmic reticulum and plays a central role in muscle relaxation. SERCA's function is regulated by single-pass membrane proteins called regulins. Unlike other regulins, dwarf open reading frame (DWORF) expressed in cardiac muscle has a unique activating effect. Here, we determine the structure and topology of DWORF in lipid bilayers using a combination of oriented sample solid-state NMR spectroscopy and replica-averaged orientationally restrained molecular dynamics. We found that DWORF's structural topology consists of a dynamic N-terminal domain, an amphipathic juxtamembrane helix that crosses the lipid groups at an angle of 64°, and a transmembrane C-terminal helix with an angle of 32°. A kink induced by Pro15, unique to DWORF, separates the two helical domains. A single Pro15Ala mutant significantly decreases the kink and eliminates DWORF's activating effect on SERCA. Overall, our findings directly link DWORF's structural topology to its activating effect on SERCA.

Original languageEnglish (US)
Pages (from-to)360-370.e6
JournalStructure
Volume30
Issue number3
DOIs
StatePublished - Mar 3 2022

Bibliographical note

Funding Information:
D.K.W. was supported by an American Heart Association postdoctoral fellowship (19POST34420009). This work was supported by National Heart, Lung, and Blood Institute grants HL143816 to S.R. and G.V. and HL092321 to S.R. We thank Caitlin Walker for her assistance with cloning the DWORF P15A expression construct and Dr. Maximo Sanz-Hernández for his contributions to the modeling work.

Publisher Copyright:
© 2021 Elsevier Ltd

Keywords

  • Ca signaling
  • Ca transport
  • SERCA activation
  • membrane protein-protein interactions
  • membrane proteins
  • oriented samples
  • solid-state NMR
  • structural topology

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