| Structural highlights
Function
[RHOB_HUMAN] Mediates apoptosis in neoplastically transformed cells after DNA damage. Not essential for development but affects cell adhesion and growth factor signaling in transformed cells. Plays a negative role in tumorigenesis as deletion causes tumor formation. Involved in intracellular protein trafficking of a number of proteins. Targets PKN1 to endosomes and is involved in trafficking of the EGF receptor from late endosomes to lysosomes. Also required for stability and nuclear trafficking of AKT1/AKT which promotes endothelial cell survival during vascular development. Serves as a microtubule-dependent signal that is required for the myosin contractile ring formation during cell cycle cytokinesis. Required for genotoxic stress-induced cell death in breast cancer cells.[1] [2] [3] [4] [5]
Publication Abstract from PubMed
The selective downregulation of activated intracellular proteins is a key challenge in cell biology. RHO small GTPases switch between a guanosine diphosphate (GDP)-bound and a guanosine triphosphate (GTP)-bound state that drives downstream signaling. At present, no tool is available to study endogenous RHO-GTPinduced conformational changes in live cells. Here, we established a cell-based screen to selectively degrade RHOB-GTP using F-box-intracellular single-domain antibody fusion. We identified one intracellular antibody (intrabody) that shows selective targeting of endogenous RHOB-GTP mediated by interactions between the CDR3 loop of the domain antibody and the GTP-binding pocket of RHOB. Our results suggest that, while RHOB is highly regulated at the expression level, only the GTP-bound pool, but not its global expression, mediates RHOB functions in genomic instability and in cell invasion. The F-box/intrabody-targeted protein degradation represents a unique approach to knock down the active form of small GTPases or other proteins with multiple cellular activities.
A Targeted Protein Degradation Cell-Based Screening for Nanobodies Selective toward the Cellular RHOB GTP-Bound Conformation.,Bery N, Keller L, Soulie M, Gence R, Iscache AL, Cherier J, Cabantous S, Sordet O, Lajoie-Mazenc I, Pedelacq JD, Favre G, Olichon A Cell Chem Biol. 2019 Nov 21;26(11):1544-1558.e6. doi:, 10.1016/j.chembiol.2019.08.009. Epub 2019 Sep 12. PMID:31522999[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Mellor H, Flynn P, Nobes CD, Hall A, Parker PJ. PRK1 is targeted to endosomes by the small GTPase, RhoB. J Biol Chem. 1998 Feb 27;273(9):4811-4. PMID:9478917
- ↑ Gampel A, Parker PJ, Mellor H. Regulation of epidermal growth factor receptor traffic by the small GTPase rhoB. Curr Biol. 1999 Sep 9;9(17):955-8. PMID:10508588
- ↑ Wherlock M, Gampel A, Futter C, Mellor H. Farnesyltransferase inhibitors disrupt EGF receptor traffic through modulation of the RhoB GTPase. J Cell Sci. 2004 Jul 1;117(Pt 15):3221-31. PMID:15226397 doi:http://dx.doi.org/10.1242/jcs.01193
- ↑ Kamijo K, Ohara N, Abe M, Uchimura T, Hosoya H, Lee JS, Miki T. Dissecting the role of Rho-mediated signaling in contractile ring formation. Mol Biol Cell. 2006 Jan;17(1):43-55. Epub 2005 Oct 19. PMID:16236794 doi:10.1091/mbc.E05-06-0569
- ↑ Srougi MC, Burridge K. The nuclear guanine nucleotide exchange factors Ect2 and Net1 regulate RhoB-mediated cell death after DNA damage. PLoS One. 2011 Feb 23;6(2):e17108. doi: 10.1371/journal.pone.0017108. PMID:21373644 doi:10.1371/journal.pone.0017108
- ↑ Bery N, Keller L, Soulie M, Gence R, Iscache AL, Cherier J, Cabantous S, Sordet O, Lajoie-Mazenc I, Pedelacq JD, Favre G, Olichon A. A Targeted Protein Degradation Cell-Based Screening for Nanobodies Selective toward the Cellular RHOB GTP-Bound Conformation. Cell Chem Biol. 2019 Nov 21;26(11):1544-1558.e6. doi:, 10.1016/j.chembiol.2019.08.009. Epub 2019 Sep 12. PMID:31522999 doi:http://dx.doi.org/10.1016/j.chembiol.2019.08.009
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