PUBLICATION
The RhoA GEF Syx is a target of Rnd3 and regulated via a Raf1-like ubiquitin-related domain
- Authors
- Goh, L.L., and Manser, E.
- ID
- ZDB-PUB-100910-23
- Date
- 2010
- Source
- PLoS One 5(8): pii: e12409 (Journal)
- Registered Authors
- Manser, Ed
- Keywords
- none
- MeSH Terms
-
- Amino Acid Sequence
- Animals
- Gastrulation
- Guanine Nucleotide Exchange Factors/chemistry*
- Guanine Nucleotide Exchange Factors/isolation & purification
- Guanine Nucleotide Exchange Factors/metabolism*
- HeLa Cells
- Humans
- Mice
- Molecular Sequence Data
- Protein Binding
- Protein Structure, Tertiary
- Proto-Oncogene Proteins c-raf/metabolism*
- Ubiquitin/chemistry*
- Zebrafish
- rho GTP-Binding Proteins/chemistry
- rho GTP-Binding Proteins/isolation & purification
- rho GTP-Binding Proteins/metabolism*
- rhoA GTP-Binding Protein/chemistry
- rhoA GTP-Binding Protein/metabolism*
- PubMed
- 20811643 Full text @ PLoS One
Citation
Goh, L.L., and Manser, E. (2010) The RhoA GEF Syx is a target of Rnd3 and regulated via a Raf1-like ubiquitin-related domain. PLoS One. 5(8):pii: e12409.
Abstract
BACKGROUND: Rnd3 (RhoE) protein belongs to the unique branch of Rho family GTPases that has low intrinsic GTPase activity and consequently remains constitutively active [1], [2]. The current consensus is that Rnd1 and Rnd3 function as important antagonists of RhoA signaling primarily by activating the ubiquitous p190 RhoGAP [3], but not by inhibiting the ROCK family kinases.
METHODOLOGY/PRINCIPAL FINDINGS: Rnd3 is abundant in mouse embryonic stem (mES) cells and in an unbiased two-step affinity purification screen we identified a new Rnd3 target, termed synectin-binding RhoA exchange factor (Syx), by mass spectrometry. The Syx interaction with Rnd3 does not occur through the Syx DH domain but utilizes a region similar to the classic Raf1 Ras-binding domain (RBD), and most closely related to those in RGS12 and RGS14. We show that Syx behaves as a genuine effector of Rnd3 (and perhaps Rnd1), with binding characteristics similar to p190-RhoGAP. Morpholino-oligonucleotide knockdown of Syx in zebrafish at the one cell stage resulted in embryos with shortened anterior-posterior body axis: this phenotype was effectively rescued by introducing mouse Syx1b mRNA. A Rnd3-binding defective mutant of Syx1b mutated in the RBD (E164A/R165D) was more potent in rescuing the embryonic defects than wild-type Syx1b, showing that Rnd3 negatively regulates Syx activity in vivo.
CONCLUSIONS/SIGNIFICANCE: This study uncovers a well defined Rnd3 effector Syx which is widely expressed and directly impacts RhoA activation. Experiments conducted in vivo indicate that Rnd3 negatively regulates Syx, and that as a RhoA-GEF it plays a key role in early embryonic cell shape changes. Thus a connection to signaling via the planar cell polarity pathway is suggested.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping