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 language | English (US) |
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Pages (from-to) | 360-370.e6 |
Journal | Structure |
Volume | 30 |
Issue number | 3 |
DOIs | |
State | Published - Mar 3 2022 |
Bibliographical note
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