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Selenoprotein K Is a Peripheral ER Membrane Protein
Atinuke Odunsi1, Erfan Rahmani2, Farid Ghelichkhani1
1Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States.
Biochemistry
|June 5, 2025
Summary
Selenoprotein K (selenok) is a peripheral, not transmembrane, protein anchored to the ER
Area of Science:
- Cell biology
- Molecular biology
- Biochemistry
Background:
- Selenoprotein K (selenok) is a small, disordered ER membrane protein.
- It plays roles in protein palmitoylation, quality control, calcium homeostasis, migration, and phagocytosis.
- Selenok has been previously characterized as a single-pass transmembrane protein.
Purpose of the Study:
- To re-evaluate the membrane topology of selenoprotein K.
- To compare the topology of selenok with the related selenoprotein S (selenos).
Main Methods:
- Immunofluorescence microscopy
- Substituted cysteine accessibility method
- Selective membrane permeabilization
Main Results:
- Selenoprotein K is a peripheral membrane protein with both N- and C-termini in the cytoplasm.
- Selenoprotein S is a transmembrane protein with a cytoplasmic C-terminus and an ER lumen-exposed N-terminus.
- Selenok's cytoplasmic exposure of termini and amphipathic helix facilitates interactions with cytoplasmic partners.
Conclusions:
- Selenok's peripheral localization and exposed domains enable interactions with cytoplasmic proteins.
- This topology is crucial for selenok's function in cellular processes and disease implicated pathways.
- Findings redefine selenok's role and interaction potential within the ER membrane environment.
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