Proximity Labeling Proteomics Reveals Kv1.3 Potassium Channel Immune Interactors in Microglia.

Publisher: Elsevier Inc. on behalf of American Society for Biochemistry and Molecular Biology Country of Publication: United States NLM ID: 101125647 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1535-9484 (Electronic) Linking ISSN: 15359476 NLM ISO Abbreviation: Mol Cell Proteomics Subsets: MEDLINE

Publication: 2021- : [New York, NY] : Elsevier Inc. on behalf of American Society for Biochemistry and Molecular Biology
Original Publication: Bethesda, MD : American Society for Biochemistry and Molecular Biology, [2002-

Kv1.3 Potassium Channel*/metabolism ; Microglia*/metabolism ; Proteomics*/methods ; Toll-Like Receptor 4*/metabolism ; STAT1 Transcription Factor*/metabolism; Animals ; Mice ; Cell Line ; Toll-Like Receptor 2/metabolism ; Lipopolysaccharides/pharmacology ; Protein Binding

Microglia are resident immune cells of the brain and regulate its inflammatory state. In neurodegenerative diseases, microglia transition from a homeostatic state to a state referred to as disease-associated microglia (DAM). DAM express higher levels of proinflammatory signaling molecules, like STAT1 and TLR2, and show transitions in mitochondrial activity toward a more glycolytic response. Inhibition of Kv1.3 decreases the proinflammatory signature of DAM, though how Kv1.3 influences the response is unknown. Our goal was to identify the potential proteins interacting with Kv1.3 during transition to DAM. We utilized TurboID, a biotin ligase, fused to Kv1.3 to evaluate potential interacting proteins with Kv1.3 via mass spectrometry in BV-2 microglia following TLR4-mediated activation. Electrophysiology, Western blotting, and flow cytometry were used to evaluate Kv1.3 channel presence and TurboID biotinylation activity. We hypothesized that Kv1.3 contains domain-specific interactors that vary during a TLR4-induced inflammatory response, some of which are dependent on the PDZ-binding domain on the C terminus. We determined that the N terminus of Kv1.3 is responsible for trafficking Kv1.3 to the cell surface and mitochondria (e.g., NUDC, TIMM50). Whereas, the C terminus interacts with immune signaling proteins in a lipopolysaccharide-induced inflammatory response (e.g., STAT1, TLR2, and C3). There are 70 proteins that rely on the C-terminal PDZ-binding domain to interact with Kv1.3 (e.g., ND3, Snx3, and Sun1). Furthermore, we used Kv1.3 blockade to verify functional coupling between Kv1.3 and interferon-mediated STAT1 activation. Overall, we highlight that the Kv1.3 potassium channel functions beyond conducting the outward flux of potassium ions in an inflammatory context and that Kv1.3 modulates the activity of key immune signaling proteins, such as STAT1 and C3.
Competing Interests: Conflict of interest H. W. is an inventor on a University of California patent claiming PAP-1 for immunosuppression. This patent has been abandoned because of its short remaining patent life. The authors declare no competing interests.
(Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

R01 AG071587 United States AG NIA NIH HHS; R01 AG075820 United States AG NIA NIH HHS; R01 NS114130 United States NS NINDS NIH HHS; T32 GM145735 United States GM NIGMS NIH HHS

Keywords: Kv1.3 potassium channel; microglia; neurodegeneration; neuroinflammation; proximity labeling

0 (Kv1.3 Potassium Channel)
0 (Toll-Like Receptor 4)
0 (STAT1 Transcription Factor)
0 (Stat1 protein, mouse)
0 (Toll-Like Receptor 2)
0 (Lipopolysaccharides)
0 (Tlr4 protein, mouse)

Date Created: 20240627 Date Completed: 20240907 Latest Revision: 20241105

20241105

10.1016/j.mcpro.2024.100809

38936775