3GNI

Structure of STRAD and MO25


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.206 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

ATP and MO25alpha regulate the conformational state of the STRADalpha pseudokinase and activation of the LKB1 tumour suppressor

Zeqiraj, E.Filippi, B.M.Goldie, S.Navratilova, I.Boudeau, J.Deak, M.Alessi, D.R.van Aalten, D.M.

(2009) Plos Biol. 7: e1000126-e1000126

  • DOI: 10.1371/journal.pbio.1000126

  • PubMed Abstract: 
  • Pseudokinases lack essential residues for kinase activity, yet are emerging as important regulators of signal transduction networks. The pseudokinase STRAD activates the LKB1 tumour suppressor by forming a heterotrimeric complex with LKB1 and the sca ...

    Pseudokinases lack essential residues for kinase activity, yet are emerging as important regulators of signal transduction networks. The pseudokinase STRAD activates the LKB1 tumour suppressor by forming a heterotrimeric complex with LKB1 and the scaffolding protein MO25. Here, we describe the structure of STRADalpha in complex with MO25alpha. The structure reveals an intricate web of interactions between STRADalpha and MO25alpha involving the alphaC-helix of STRADalpha, reminiscent of the mechanism by which CDK2 interacts with cyclin A. Surprisingly, STRADalpha binds ATP and displays a closed conformation and an ordered activation loop, typical of active protein kinases. Inactivity is accounted for by nonconservative substitution of almost all essential catalytic residues. We demonstrate that binding of ATP enhances the affinity of STRADalpha for MO25alpha, and conversely, binding of MO25alpha promotes interaction of STRADalpha with ATP. Mutagenesis studies reveal that association of STRADalpha with either ATP or MO25alpha is essential for LKB1 activation. We conclude that ATP and MO25alpha cooperate to maintain STRADalpha in an "active" closed conformation required for LKB1 activation. It has recently been demonstrated that a mutation in human STRADalpha that truncates a C-terminal region of the pseudokinase domain leads to the polyhydramnios, megalencephaly, symptomatic epilepsy (PMSE) syndrome. We demonstrate this mutation destabilizes STRADalpha and prevents association with LKB1. In summary, our findings describe one of the first structures of a genuinely inactive pseudokinase. The ability of STRADalpha to activate LKB1 is dependent on a closed "active" conformation, aided by ATP and MO25alpha binding. Thus, the function of STRADalpha is mediated through an active kinase conformation rather than kinase activity. It is possible that other pseudokinases exert their function through nucleotide binding and active conformations.


    Organizational Affiliation

    Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, Scotland.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Protein Mo25
A
341Homo sapiensMutation(s): 0 
Gene Names: CAB39 (MO25)
Find proteins for Q9Y376 (Homo sapiens)
Go to Gene View: CAB39
Go to UniProtKB:  Q9Y376
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
STRAD alpha
B
389Homo sapiensMutation(s): 0 
Gene Names: STRADA (LYK5, STRAD)
Find proteins for Q7RTN6 (Homo sapiens)
Go to Gene View: STRADA
Go to UniProtKB:  Q7RTN6
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ATP
Query on ATP

Download SDF File 
Download CCD File 
B
ADENOSINE-5'-TRIPHOSPHATE
C10 H16 N5 O13 P3
ZKHQWZAMYRWXGA-KQYNXXCUSA-N
 Ligand Interaction
CIT
Query on CIT

Download SDF File 
Download CCD File 
A
CITRIC ACID
C6 H8 O7
KRKNYBCHXYNGOX-UHFFFAOYSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
ATPKd: 20 nM BINDINGMOAD
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.206 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 73.678α = 90.00
b = 82.874β = 90.00
c = 134.292γ = 90.00
Software Package:
Software NamePurpose
SCALAdata scaling
MOSFLMdata reduction
DNAdata collection
REFMACrefinement
MOLREPphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-06-16
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Advisory, Refinement description, Version format compliance