Outward-facing auxin bound form of auxin transporter PIN8

Experimental Data Snapshot

  • Resolution: 3.18 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation   3D Report Full Report

This is version 1.2 of the entry. See complete history


Structures and mechanism of the plant PIN-FORMED auxin transporter.

Ung, K.L.Winkler, M.Schulz, L.Kolb, M.Janacek, D.P.Dedic, E.Stokes, D.L.Hammes, U.Z.Pedersen, B.P.

(2022) Nature 609: 605-610

  • DOI: https://doi.org/10.1038/s41586-022-04883-y
  • Primary Citation of Related Structures:  
    7QP9, 7QPA, 7QPC

  • PubMed Abstract: 

    Auxins are hormones that have central roles and control nearly all aspects of growth and development in plants 1-3 . The proteins in the PIN-FORMED (PIN) family (also known as the auxin efflux carrier family) are key participants in this process and control auxin export from the cytosol to the extracellular space 4-9 . Owing to a lack of structural and biochemical data, the molecular mechanism of PIN-mediated auxin transport is not understood. Here we present biophysical analysis together with three structures of Arabidopsis thaliana PIN8: two outward-facing conformations with and without auxin, and one inward-facing conformation bound to the herbicide naphthylphthalamic acid. The structure forms a homodimer, with each monomer divided into a transport and scaffold domain with a clearly defined auxin binding site. Next to the binding site, a proline-proline crossover is a pivot point for structural changes associated with transport, which we show to be independent of proton and ion gradients and probably driven by the negative charge of the auxin. The structures and biochemical data reveal an elevator-type transport mechanism reminiscent of bile acid/sodium symporters, bicarbonate/sodium symporters and sodium/proton antiporters. Our results provide a comprehensive molecular model for auxin recognition and transport by PINs, link and expand on a well-known conceptual framework for transport, and explain a central mechanism of polar auxin transport, a core feature of plant physiology, growth and development.

  • Organizational Affiliation

    Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Auxin efflux carrier component 8
A, B
376Arabidopsis thalianaMutation(s): 0 
Gene Names: PIN8PIN5At5g15100F2G14_220
Membrane Entity: Yes 
Find proteins for Q9LFP6 (Arabidopsis thaliana)
Explore Q9LFP6 
Go to UniProtKB:  Q9LFP6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9LFP6
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.18 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion

Structure Validation

View Full Validation Report

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
European Research Council (ERC)European Union101000936

Revision History  (Full details and data files)

  • Version 1.0: 2022-07-06
    Type: Initial release
  • Version 1.1: 2022-07-13
    Changes: Database references
  • Version 1.2: 2022-09-28
    Changes: Database references