6CZQ

A V-to-F substitution in SK2 channels causes Ca2+ hypersensitivity and improves locomotion in a C. elegans ALS model

  • Classification: METAL TRANSPORT
  • Organism(s): Rattus norvegicus
  • Expression System: Escherichia coli
  • Mutation(s): Yes 
  • Membrane Protein: Yes  PDBTM

  • Deposited: 2018-04-09 Released: 2018-08-01 
  • Deposition Author(s): Nam, Y.W., Zhang, M.
  • Funding Organization(s): American Heart Association, National Institutes of Health/National Institute of Neurological Disorders and Stroke (NIH/NINDS)

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.201 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

A V-to-F substitution in SK2 channels causes Ca2+hypersensitivity and improves locomotion in a C. elegans ALS model.

Nam, Y.W.Baskoylu, S.N.Gazgalis, D.Orfali, R.Cui, M.Hart, A.C.Zhang, M.

(2018) Sci Rep 8: 10749-10749

  • DOI: 10.1038/s41598-018-28783-2
  • Primary Citation of Related Structures:  
    6ALE, 6CZQ

  • PubMed Abstract: 
  • Small-conductance Ca 2+ -activated K + (SK) channels mediate medium afterhyperpolarization in the neurons and play a key role in the regulation of neuronal excitability. SK channels are potential drug targets for ataxia and Amyotrophic Lateral Sclerosis (ALS) ...

    Small-conductance Ca 2+ -activated K + (SK) channels mediate medium afterhyperpolarization in the neurons and play a key role in the regulation of neuronal excitability. SK channels are potential drug targets for ataxia and Amyotrophic Lateral Sclerosis (ALS). SK channels are activated exclusively by the Ca 2+ -bound calmodulin. Previously, we identified an intrinsically disordered fragment that is essential for the mechanical coupling between Ca 2+ /calmodulin binding and channel opening. Here, we report that substitution of a valine to phenylalanine (V407F) in the intrinsically disordered fragment caused a ~6 fold increase in the Ca 2+ sensitivity of SK2-a channels. This substitution resulted in a novel interaction between the ectopic phenylalanine and M411, which stabilized PIP 2 -interacting residue K405, and subsequently enhanced Ca 2+ sensitivity. Also, equivalent valine to phenylalanine substitutions in SK1 or SK3 channels conferred Ca 2+ hypersensitivity. An equivalent phenylalanine substitution in the Caenorhabditis elegans (C. elegans) SK2 ortholog kcnl-2 partially rescued locomotion defects in an existing C. elegans ALS model, in which human SOD1G85R is expressed at high levels in neurons, confirming that this phenylalanine substitution impacts channel function in vivo. This work for the first time provides a critical reagent for future studies: an SK channel that is hypersensitive to Ca 2+ with increased activity in vivo.


    Organizational Affiliation

    Department of Biomedical and Pharmaceutical Sciences & Structural Biology Research Center, Chapman University School of Pharmacy, Irvine, California, 92618, USA. zhang@chapman.edu.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Small conductance calcium-activated potassium channel protein 2A [auth B]95Rattus norvegicusMutation(s): 2 
Gene Names: Kcnn2
Membrane Entity: Yes 
UniProt
Find proteins for P70604 (Rattus norvegicus)
Explore P70604 
Go to UniProtKB:  P70604
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Calmodulin-1B [auth R]146Rattus norvegicusMutation(s): 0 
Gene Names: Calm1CalmCamCam1CaMI
UniProt
Find proteins for P0DP29 (Rattus norvegicus)
Explore P0DP29 
Go to UniProtKB:  P0DP29
Protein Feature View
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  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.201 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 76.273α = 90
b = 66.726β = 92.19
c = 64.676γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
APEX 2data scaling
PDB_EXTRACTdata extraction
XPREPdata reduction
PHASERphasing

Structure Validation

View Full Validation Report




Entry History & Funding Information

Deposition Data

  • Deposited Date: 2018-04-09 
  • Released Date: 2018-08-01 
  • Deposition Author(s): Nam, Y.W., Zhang, M.

Funding OrganizationLocationGrant Number
American Heart AssociationUnited States13SDG16150007
National Institutes of Health/National Institute of Neurological Disorders and Stroke (NIH/NINDS)United States1 R21 NS101182-01A1

Revision History  (Full details and data files)

  • Version 1.0: 2018-08-01
    Type: Initial release
  • Version 1.1: 2019-12-18
    Changes: Author supporting evidence