7NIP

titin N2A unique sequence (UN2A) core


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 32500 
  • Conformers Submitted: 10 
  • Selection Criteria: all calculated structures submitted 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Molecular Characterisation of Titin N2A and Its Binding of CARP Reveals a Titin/Actin Cross-linking Mechanism.

Zhou, T.Fleming, J.R.Lange, S.Hessel, A.L.Bogomolovas, J.Stronczek, C.Grundei, D.Ghassemian, M.Biju, A.Borgeson, E.Bullard, B.Linke, W.A.Chen, J.Kovermann, M.Mayans, O.

(2021) J Mol Biol 433: 166901-166901

  • DOI: https://doi.org/10.1016/j.jmb.2021.166901
  • Primary Citation of Related Structures:  
    7NIP

  • PubMed Abstract: 

    Striated muscle responds to mechanical overload by rapidly up-regulating the expression of the cardiac ankyrin repeat protein, CARP, which then targets the sarcomere by binding to titin N2A in the I-band region. To date, the role of this interaction in the stress response of muscle remains poorly understood. Here, we characterise the molecular structure of the CARP-receptor site in titin (UN2A) and its binding of CARP. We find that titin UN2A contains a central three-helix bundle fold (ca 45 residues in length) that is joined to N- and C-terminal flanking immunoglobulin domains by long, flexible linkers with partial helical content. CARP binds titin by engaging an α-hairpin in the three-helix fold of UN2A, the C-terminal linker sequence, and the BC loop in Ig81, which jointly form a broad binding interface. Mutagenesis showed that the CARP/N2A association withstands sequence variations in titin N2A and we use this information to evaluate 85 human single nucleotide variants. In addition, actin co-sedimentation, co-transfection in C2C12 cells, proteomics on heart lysates, and the mechanical response of CARP-soaked myofibrils imply that CARP induces the cross-linking of titin and actin myofilaments, thereby increasing myofibril stiffness. We conclude that CARP acts as a regulator of force output in the sarcomere that preserves muscle mechanical performance upon overload stress.


  • Organizational Affiliation

    Department of Biology, University of Konstanz, 78457 Konstanz, Germany.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Isoform 11 of Titin41Homo sapiensMutation(s): 0 
Gene Names: TTN
EC: 2.7.11.1
UniProt & NIH Common Fund Data Resources
Find proteins for Q8WZ42 (Homo sapiens)
Explore Q8WZ42 
Go to UniProtKB:  Q8WZ42
PHAROS:  Q8WZ42
GTEx:  ENSG00000155657 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8WZ42
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 32500 
  • Conformers Submitted: 10 
  • Selection Criteria: all calculated structures submitted 

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Leducq FoundationFranceTNE-13CVD04
H2020 Marie Curie Actions of the European CommissionEuropean Union753054

Revision History  (Full details and data files)

  • Version 1.0: 2021-03-03
    Type: Initial release
  • Version 1.1: 2021-03-17
    Changes: Database references
  • Version 1.2: 2021-03-31
    Changes: Database references
  • Version 1.3: 2024-06-19
    Changes: Data collection, Database references