7PDZ

Structure of capping protein bound to the barbed end of a cytoplasmic actin filament


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.80 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

A barbed end interference mechanism reveals how capping protein promotes nucleation in branched actin networks.

Funk, J.Merino, F.Schaks, M.Rottner, K.Raunser, S.Bieling, P.

(2021) Nat Commun 12: 5329-5329

  • DOI: 10.1038/s41467-021-25682-5
  • Primary Citation of Related Structures:  
    7PDZ

  • PubMed Abstract: 
  • Heterodimeric capping protein (CP/CapZ) is an essential factor for the assembly of branched actin networks, which push against cellular membranes to drive a large variety of cellular processes. Aside from terminating filament growth, CP potentiates the nucleation of actin filaments by the Arp2/3 complex in branched actin networks through an unclear mechanism ...

    Heterodimeric capping protein (CP/CapZ) is an essential factor for the assembly of branched actin networks, which push against cellular membranes to drive a large variety of cellular processes. Aside from terminating filament growth, CP potentiates the nucleation of actin filaments by the Arp2/3 complex in branched actin networks through an unclear mechanism. Here, we combine structural biology with in vitro reconstitution to demonstrate that CP not only terminates filament elongation, but indirectly stimulates the activity of Arp2/3 activating nucleation promoting factors (NPFs) by preventing their association to filament barbed ends. Key to this function is one of CP's C-terminal "tentacle" extensions, which sterically masks the main interaction site of the terminal actin protomer. Deletion of the β tentacle only modestly impairs capping. However, in the context of a growing branched actin network, its removal potently inhibits nucleation promoting factors by tethering them to capped filament ends. End tethering of NPFs prevents their loading with actin monomers required for activation of the Arp2/3 complex and thus strongly inhibits branched network assembly both in cells and reconstituted motility assays. Our results mechanistically explain how CP couples two opposed processes-capping and nucleation-in branched actin network assembly.


    Organizational Affiliation

    Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany. Peter.Bieling@mpi-dortmund.mpg.de.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Isoform 2 of F-actin-capping protein subunit betaA [auth E]272Mus musculusMutation(s): 0 
Gene Names: CapzbCappb1
UniProt & NIH Common Fund Data Resources
Find proteins for P47757 (Mus musculus)
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Go to UniProtKB:  P47757
IMPC:  MGI:104652
Protein Feature View
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  • Reference Sequence
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
F-actin-capping protein subunit alpha-1B [auth F]286Mus musculusMutation(s): 0 
Gene Names: Capza1Cappa1
UniProt
Find proteins for P47753 (Mus musculus)
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Go to UniProtKB:  P47753
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  • Reference Sequence
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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
Actin, cytoplasmic 1C [auth I], D [auth J], E [auth K], F [auth L], G [auth N], H [auth O]375Bos taurusMutation(s): 0 
Gene Names: ACTB
UniProt
Find proteins for P60712 (Bos taurus)
Explore P60712 
Go to UniProtKB:  P60712
Protein Feature View
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  • Reference Sequence

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Entity ID: 4
MoleculeChainsSequence LengthOrganismDetailsImage
PhalloidinM [auth P], I [auth Q], J [auth R], K [auth S], L [auth T]7synthetic constructMutation(s): 0 
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ADP (Subject of Investigation/LOI)
Query on ADP

Download Ideal Coordinates CCD File 
AA [auth O], N [auth I], P [auth J], S [auth K], U [auth L], X [auth N]ADENOSINE-5'-DIPHOSPHATE
C10 H15 N5 O10 P2
XTWYTFMLZFPYCI-KQYNXXCUSA-N
 Ligand Interaction
PO4 (Subject of Investigation/LOI)
Query on PO4

Download Ideal Coordinates CCD File 
CA [auth O], R [auth K], W [auth L], Z [auth N]PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
MG (Subject of Investigation/LOI)
Query on MG

Download Ideal Coordinates CCD File 
BA [auth O], O [auth I], Q [auth J], T [auth K], V [auth L], Y [auth N]MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  2 Unique
IDChainsTypeFormula2D DiagramParent
HIC
Query on HIC
C [auth I], D [auth J], E [auth K], F [auth L], G [auth N], H [auth O]L-PEPTIDE LINKINGC7 H11 N3 O2HIS
HYP
Query on HYP
I [auth Q], J [auth R], K [auth S], L [auth T], M [auth P]L-PEPTIDE LINKINGC5 H9 N O3PRO
Biologically Interesting Molecules (External Reference) 1 Unique
Entity ID: 4
IDChainsNameType/Class2D Diagram3D Interactions
PRD_002307
Query on PRD_002307
I [auth P], J [auth Q], K [auth R], L [auth S], M [auth T]PhalloidinCyclic peptide / Toxin Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.80 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Max Planck SocietyGermany--

Revision History  (Full details and data files)

  • Version 1.0: 2021-09-01
    Type: Initial release
  • Version 1.1: 2021-10-06
    Changes: Data collection, Database references