Ras-associating (RA) domain found in Ral guanine nucleotide dissociation stimulator-like 3 (RalGDS-like 3) and similar proteins
RalGDS-like 3 (RGL3), also termed Ras pathway modulator (RPM), interacts in a GTP- and effector loop-dependent manner with Rit and Ras. As a novel potential effector of both p21 Ras and M-Ras, RGL3 negatively regulates Elk-1-dependent gene induction downstream of p21 Ras or mitogen activated protein/extracellular signal regulated kinase Kinase 1 (MEKK1). It also functions as a potential binding partner for Rap-family small G-proteins and profilin II. RGL3 belongs to RalGDS family, whose members are involved in Ras and Ral signaling pathways as downstream effector proteins. Members in this family have similar domain structure: a central CDC25 homology domain with an upstream Ras Exchange motif (REM), and a C-terminal Ras-associating (RA) domain. The RA domain has the beta-grasp ubiquitin-like fold with low sequence similarity to ubiquitin; ubiquitin is a protein modifier (Ubiquitination) in eukaryotes that is involved in various cellular processes including transcriptional regulation, cell cycle control, and DNA repair.
Feature 1:putative RA-Ras interaction site [polypeptide binding site]
Evidence:
Comment:Based on the structural evidence that Rattus norvegicus RA domain of RalGDS (1LFD) in complex with Ras, contacts at 4A.
Comment:All RA domains have the common ubiquitin fold but not all of them bind to Ras proteins
Comment:Computational and manual sequence and structure analysis of RA domains show the positively charged sequence epitopes of its ubiquitin fold (beta1, beta2 and alpha1) which are located at similar positions are the hot spots of the binding interface to Ras.
Comment:The Ras protein signals to a number of distinct pathways by interacting with diverse downstream effectors. In the case of the Ras-RA_RalGDs complex a second RA_RalGDS molecule also interacts with a different part of the Ras molecule.
Jiyao W et al.(2023). "The conserved domain database in 2023.",