5DSE

Crystal Structure of the TTC7B/Hyccin Complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.90 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.212 
  • R-Value Observed: 0.213 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

The leukodystrophy protein FAM126A (hyccin) regulates PtdIns(4)P synthesis at the plasma membrane.

Baskin, J.M.Wu, X.Christiano, R.Oh, M.S.Schauder, C.M.Gazzerro, E.Messa, M.Baldassari, S.Assereto, S.Biancheri, R.Zara, F.Minetti, C.Raimondi, A.Simons, M.Walther, T.C.Reinisch, K.M.De Camilli, P.

(2016) Nat Cell Biol 18: 132-138

  • DOI: 10.1038/ncb3271
  • Primary Citation of Related Structures:  
    5DSE

  • PubMed Abstract: 
  • Genetic defects in myelin formation and maintenance cause leukodystrophies, a group of white matter diseases whose mechanistic underpinnings are poorly understood. Hypomyelination and congenital cataract (HCC), one of these disorders, is caused by mutations in FAM126A, a gene of unknown function ...

    Genetic defects in myelin formation and maintenance cause leukodystrophies, a group of white matter diseases whose mechanistic underpinnings are poorly understood. Hypomyelination and congenital cataract (HCC), one of these disorders, is caused by mutations in FAM126A, a gene of unknown function. We show that FAM126A, also known as hyccin, regulates the synthesis of phosphatidylinositol 4-phosphate (PtdIns(4)P), a determinant of plasma membrane identity. HCC patient fibroblasts exhibit reduced PtdIns(4)P levels. FAM126A is an intrinsic component of the plasma membrane phosphatidylinositol 4-kinase complex that comprises PI4KIIIα and its adaptors TTC7 and EFR3 (refs 5,7). A FAM126A-TTC7 co-crystal structure reveals an all-α-helical heterodimer with a large protein-protein interface and a conserved surface that may mediate binding to PI4KIIIα. Absence of FAM126A, the predominant FAM126 isoform in oligodendrocytes, destabilizes the PI4KIIIα complex in mouse brain and patient fibroblasts. We propose that HCC pathogenesis involves defects in PtdIns(4)P production in oligodendrocytes, whose specialized function requires massive plasma membrane expansion and thus generation of PtdIns(4)P and downstream phosphoinositides. Our results point to a role for FAM126A in supporting myelination, an important process in development and also following acute exacerbations in multiple sclerosis.


    Organizational Affiliation

    Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, Connecticut  06510, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Tetratricopeptide repeat protein 7BA, C837Homo sapiensMutation(s): 0 
Gene Names: TTC7BTTC7L1
UniProt & NIH Common Fund Data Resources
Find proteins for Q86TV6 (Homo sapiens)
Explore Q86TV6 
Go to UniProtKB:  Q86TV6
PHAROS:  Q86TV6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ86TV6
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
HyccinB, D312Homo sapiensMutation(s): 0 
Gene Names: FAM126ADRCTNNB1A
UniProt & NIH Common Fund Data Resources
Find proteins for Q9BYI3 (Homo sapiens)
Explore Q9BYI3 
Go to UniProtKB:  Q9BYI3
PHAROS:  Q9BYI3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9BYI3
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.90 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.212 
  • R-Value Observed: 0.213 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 71.779α = 90
b = 168.068β = 90
c = 239.671γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data scaling
SHELXphasing
Cootmodel building

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2015-12-02
    Type: Initial release
  • Version 1.1: 2016-01-13
    Changes: Database references
  • Version 1.2: 2017-11-22
    Changes: Derived calculations, Refinement description