Identification, expression analysis, genomic organization and cellular location of a novel protein with a RhoGEF domain
Introduction
Guanine exchange factors (GEF) stimulate Rho and Rac signal transduction molecules by switching them from the inactive (GDP-bound) to the active (GTP-bound) form. These molecules are often involved in organizing the cytoskeleton and act as axon guidance molecules (Schmidt and Hall, 2002). In a yeast two-hybrid screen aimed to identify proteins interacting with the hinge domain of tau, we isolated a cDNA corresponding to predicted human protein FLJ00128/FLJ10357. Here we report the genomic organization, expression analysis and cellular localization of this novel gene and its product, which we named Solo to reflect its homology to Duo, Duet, Trio and Quattro (members of the RhoGEF superfamily; Erickson and Cerione, 2004). The C-terminus of the deduced Solo protein sequence contains a RhoGEF domain followed by a pleckstrin domain, and three of its regions are homologous to equivalent regions of the zebrafish Quattro protein, which is involved in morphogenetic movements mediated by the actin cytoskeleton (Daggett et al., 2004). The Solo transcript varies in different tissues and developmental stages and also undergoes extensive alternative splicing, which influences the length of its reading frame.
Section snippets
Yeast two-hybrid assay
We used the Clontech GAL4 yeast two-hybrid system to identify proteins interacting with the hinge region of tau. The bait contained human tau exons 5 and 6 (56 and 198 nt, respectively) and the first 80 nucleotides of tau exon 7. To prepare it, we inserted a 230 bp EcoRI/NotI tau cDNA fragment into vector pGBT9 (Clontech). Afterwards, we filled in the EcoRI site to create an AseI site, so that the fusion protein would have the correct reading frame in its tau portion.
The 5/6/7 bait and a rat
Sequence analysis, chromosomal location and genomic organization of Solo
The mp31 cDNA encodes a novel protein with RhoGEF and pleckstrin (PH) domains at its C-terminal region. These domains are found in proteins which stimulate Rho and Rac signal transduction molecules by switching them from the inactive (GDP-bound) to the active (GTP-bound) form. These molecules often help to organize the cytoskeleton and act as axon guidance molecules (Schmidt and Hall, 2002). Among them are Duo (Huntingtin-associated protein interactor 1), Duet and Trio (kalirin, unc73). In
Discussion
Rearrangements of the cytoskeleton, which consists of actin filaments, microtubules, and intermediate filaments, are required for various cellular processes, such as morphology changes, migration, adhesion and cytokinesis (Etienne-Manneville, 2004). These temporal and spatial reorganizations of cell structure and cell contacts can be stimulated by extracellular signals, including growth factors, hormones, and other biologically active substances. Members of the Rho GTPase family of
Acknowledgments
This study was supported by NICHD grant HD05515 to A.A. and P.M. We wish to thank John Memmott for expert technical assistance.
References (20)
- et al.
The Dbl family of oncogenes
Curr. Opin. Cell Biol.
(1996) Developmentally restricted actin-regulatory molecules control morphogenetic cell movements in the zebrafish gastrula
Curr. Biol.
(2004)- et al.
Signaling to the Rho GTPases: networking with the DH domain
FEBS Lett.
(2002) - et al.
Cell migration: rho GTPases lead the way
Dev. Biol.
(2004) - et al.
Dbl family proteins
Biochim. Biophys. Acta
(1997) Dynamic and coordinated expression profile of dbl-family guanine nucleotide exchange factors in the developing mouse brain
Gene Expr. Patterns
(2003)- et al.
The Trio family of guanine-nucleotide-exchange factors: regulators of axon guidance
J. Cell. Sci.
(2001) - et al.
Autoinhibition mechanism of proto-Dbl
Mol. Cell. Biol.
(2001) - et al.
Structural elements, mechanism, and evolutionary convergence of Rho protein-guanine nucleotide exchange factor complexes
Biochemistry
(2004) Actin and microtubules in cell motility: which one is in control?
Traffic
(2004)
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