3GNI

Structure of STRAD and MO25

PDB DOI: 10.2210/pdb3GNI/pdb

Classification: SIGNALING PROTEIN/SIGNALING PROTEIN
Organism(s): Homo sapiens
Expression System: Escherichia coli
Mutation(s): No

Deposited: 2009-03-17 Released: 2009-06-16
Deposition Author(s): Zeqiraj, E., Goldie, S., Alessi, D.R., van Aalten, D.M.F.

Experimental Data Snapshot

Method: X-RAY DIFFRACTION
Resolution: 2.35 Å
R-Value Free: 0.254
R-Value Work: 0.206
R-Value Observed: 0.207

wwPDB Validation 3D Report Full Report

Ligand Structure Quality Assessment

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

PubMed: 19513107 Search on PubMedSearch on PubMed Central
DOI: 10.1371/journal.pbio.1000126
Primary Citation of Related Structures:
3GNI

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 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

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(by identity cutoff) | 3D Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Protein Mo25	A	341	Homo sapiens	Mutation(s): 0 Gene Names: CAB39, MO25, CGI-66
UniProt & NIH Common Fund Data Resources
Find proteins for Q9Y376 (Homo sapiens) Explore Q9Y376 Go to UniProtKB: Q9Y376
PHAROS: Q9Y376
Entity Groups
Sequence Clusters	30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt Group	Q9Y376
Protein Feature View Expand
Reference Sequence

Find similar proteins by:

(by identity cutoff) | 3D Structure

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
STRAD alpha	B	389	Homo sapiens	Mutation(s): 0 Gene Names: STRADA, LYK5, STRAD
UniProt & NIH Common Fund Data Resources
Find proteins for Q7RTN6 (Homo sapiens) Explore Q7RTN6 Go to UniProtKB: Q7RTN6
PHAROS: Q7RTN6
Entity Groups
Sequence Clusters	30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt Group	Q7RTN6
Protein Feature View Expand
Reference Sequence

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram	3D Interactions
ATP Query on ATP Download Ideal Coordinates CCD File SDF format, chain D [auth B] MOL2 format, chain D [auth B]	D [auth B]	ADENOSINE-5'-TRIPHOSPHATE C₁₀ H₁₆ N₅ O₁₃ P₃ ZKHQWZAMYRWXGA-KQYNXXCUSA-N		Ligand Interaction
CIT Query on CIT Download Ideal Coordinates CCD File SDF format, chain C [auth A] MOL2 format, chain C [auth A]	C [auth A]	CITRIC ACID C₆ H₈ O₇ KRKNYBCHXYNGOX-UHFFFAOYSA-N		Ligand Interaction