PDBsum entry: 2nz8

Signaling protein,cell cycle

PDB id: 2nz8

Contents

Protein chains

177 a.a. *

279 a.a. *

Waters ×242

* Residue conservation analysis

PDB id:

2nz8

Name:

Signaling protein,cell cycle

Title:

N-terminal dhph cassette of trio in complex with nucleotide- free rac1

Structure:

Ras-related c3 botulinum toxin substrate 1 isoform rac1. Chain: a. Fragment: soluble part (residues 1-177). Synonym: ras-related c3 botulinum toxin substrate 1. P21- rac1. Ras-like protein tc25. Engineered: yes. Triple functional domain protein. Chain: b.

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: rac1. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008. Gene: trio.

Resolution:

2.00Å R-factor: 0.225 R-free: 0.249

Authors:

M.K.Chhatriwala,L.Betts,D.K.Worthylake,J.Sondek

Key ref:

M.K.Chhatriwala et al. (2007). The DH and PH Domains of Trio Coordinately Engage Rho GTPases for their Efficient Activation. J Mol Biol, 368, 1307-1320. PubMed id: 17391702 DOI: 10.1016/j.jmb.2007.02.060

Date:

22-Nov-06 Release date: 10-Apr-07

Protein chain

P63000  (RAC1_HUMAN) -  Ras-related C3 botulinum toxin substrate 1

Seq: 192 a.a.

Struc: 177 a.a.

Protein chain

O75962  (TRIO_HUMAN) -  Triple functional domain protein

Seq: 3097 a.a.

Struc: 279 a.a.

Enzyme reactions

• Enzyme class: Chain B: E.C.2.7.11.1 - Non-specific serine/threonine protein kinase.
• Reaction: ATP + a protein = ADP + a phosphoprotein

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

 Gene Ontology (GO) functional annotation 

• Cellular component: intracellular (5 terms)
• Biological process: cell adhesion (20 terms)
• Biochemical function: nucleotide binding (8 terms)

reference

DOI no: 10.1016/j.jmb.2007.02.060

J Mol Biol 368:1307-1320 (2007)

PubMed id: 17391702

The DH and PH Domains of Trio Coordinately Engage Rho GTPases for their Efficient Activation.

M.K.Chhatriwala, L.Betts, D.K.Worthylake, J.Sondek.

ABSTRACT

Rho-family GTPases are activated by the exchange of bound GDP for GTP, a process that is catalyzed by Dbl-family guanine nucleotide exchange factors (GEFs). The catalytic unit of Dbl-family GEFs consists of a Dbl homology (DH) domain followed almost invariantly by a pleckstrin-homology (PH) domain. The majority of the catalytic interface forms between the switch regions of the GTPase and the DH domain, but full catalytic activity often requires the associated PH domain. Although PH domains are usually characterized as lipid-binding regions, they also participate in protein-protein interactions. For example, the DH-associated PH domain of Dbs must contact its cognate GTPases for efficient exchange. Similarly, the N-terminal DH/PH fragment of Trio, which catalyzes exchange on both Rac1 and RhoG, is fourfold more active in vitro than the isolated DH domain. Given continued uncertainty regarding functional roles of DH-associated PH domains, we have undertaken structural and functional analyses of the N-terminal DH/PH cassette of Trio. The crystal structure of this fragment of Trio bound to nucleotide-depleted Rac1 highlights the engagement of the PH domain with Rac1 and substitution of residues involved in this interface substantially diminishes activation of Rac1 and RhoG. Also, these mutations significantly reduce the ability of full-length Trio to induce neurite outgrowth dependent on RhoG activation in PC-12 cells. Overall, these studies substantiate a general role for DH-associated PH domains in engaging Rho GTPases directly for efficient guanine nucleotide exchange and support a parsimonious explanation for the essentially invariant linkage between DH and PH domains.

Selected figure(s)

Figure 1.
Figure 1. Trio-related GEFs. (a) Crystallized fragment of Trio is highlighted within the domain architecture of full-length Trio. (b) Residues of Dbs (arrows) that mediate contacts between its N-terminal PH domain and cognate GTPases are conserved in other Dbl-family GEFs, including Trio. The relative position of these residues in context of the DH/PH cassette is indicated in Figure 3.

Figure 2.
Figure 2. Crystal structure of the DH/PH fragment of Trio bound to nucleotide-free Rac1. (a) The N-terminal DH (yellow) and PH (blue) domains of Trio are bound to nucleotide-depleted Rac1 (green with switch regions in red). Disordered regions are indicated with dotted lines. (b) Atomic details of the interface between Rac1 and the PH domain of Trio. Hydrogen bonds (2.6–4.0 Å) are indicated with dotted lines (c) A simulated annealing omit map (left) contoured at 1.0σ and a 2F[o]–F[c] map (right) contoured at 1.2σ generated using the final coordinates highlight the electron density at the interface between Rac1 and the PH domain. (d) The anisotropic motion of each atom is displayed as a thermal ellipse (left). An identical image without the thermal ellipses is shown as a reference (right). The interface between Rac1 and the PH domain of Trio, also depicted in (b) and (c), is highlighted by the box.

The above figures are reprinted from an Open Access publication published by Elsevier: J Mol Biol (2007, 368, 1307-1320) copyright 2007.

Figures were selected by the author.