6SGE

Crystal structure of Human RHOB-GTP in complex with nanobody B6

Summary for 6SGE

• Entry DOI: 10.2210/pdb6sge/pdb
• Descriptor: Rho-related GTP-binding protein RhoB, Nanobody B6, GUANOSINE-5'-TRIPHOSPHATE, ... (5 entities in total)
• Functional Keywords: gtpase, rho, antibody, complex, immune system
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 4
• Total formula weight: 72181.78

Authors

Soulie, S.,Gence, R.,Cabantous, S.,Lajoie-Mazenc, I.,Favre, G.,Pedelacq, J.D. (deposition date: 2019-08-04, release date: 2019-09-25, Last modification date: 2024-01-24)

Primary citation

Bery, N.,Keller, L.,Soulie, M.,Gence, R.,Iscache, A.L.,Cherier, J.,Cabantous, S.,Sordet, O.,Lajoie-Mazenc, I.,Pedelacq, J.D.,Favre, G.,Olichon, A.
A Targeted Protein Degradation Cell-Based Screening for Nanobodies Selective toward the Cellular RHOB GTP-Bound Conformation.
Cell Chem Biol, 26:1544-, 2019

PubMed Abstract: 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.

PubMed: 31522999
DOI: 10.1016/j.chembiol.2019.08.009

Experimental method

X-RAY DIFFRACTION (1.5 Å)