Mitochondrial division is a highly regulated process. The master regulator of this process is the multi-domain, conserved protein called Dnm1 in yeast. In this study, we systematically analyzed two residues, T62 and S277, reported to be putatively phosphorylated in the GTPase domain of the protein. These residues lie in the G2 and G5 motifs of the GTPase domain. Both residues are important for the function of the protein, as evident from in vivo and in vitro analysis of the non-phosphorylatable and phosphomimetic variants. Dnm1 and Dnm1 showed differences with respect to the protein localization and puncta dynamics in vivo, albeit both were non-functional as assessed by mitochondrial morphology and GTPase activity. Overall, the secondary structure of the protein variants was unaltered, but local conformational changes were observed. Interestingly, both Dnm1 and Dnm1 exhibited dominant-negative behavior when expressed in cells containing endogenous Dnm1. To our knowledge, we report for the first time a single residue (S277) change that does not alter the localization of Dnm1 but makes it non-functional in a dominant-negative manner. Intriguingly, the two residues analyzed in this study are present in the same domain but exhibit variable effects when mutated to alanine or aspartic acid.
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http://dx.doi.org/10.1016/j.ijbiomac.2023.127381 | DOI Listing |
Biochemistry
December 2024
Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India.
The Ras GTPase-activating protein SH3-domain-binding protein 1 (G3BP1) serves as a formidable barrier to viral replication by generating stress granules (SGs) in response to viral infections. Interestingly, viruses, including SARS-CoV-2, have evolved defensive mechanisms to hijack SG proteins like G3BP1 for the dissipation of SGs that lead to the evasion of the host's immune responses. Previous research has demonstrated that the interaction between the NTF2-like domain of G3BP1 (G3BP1) and the intrinsically disordered N-terminal domain (NTD-N) of the N-protein plays a crucial role in regulating viral replication and pathogenicity.
View Article and Find Full Text PDFThe Parkinson's disease (PD)-linked protein Leucine-Rich Repeat Kinase 2 (LRRK2) consists of seven domains, including a kinase and a Roc G domain. Despite the availability of several high-resolution structures, the dynamic regulation of its unique intramolecular domain stack is nevertheless still not well understood. By in-depth biochemical analysis, assessing the Michaelis-Menten kinetics of the Roc G domain, we have confirmed that LRRK2 has, similar to other Roco protein family members, a K value of LRRK2 that lies within the range of the physiological GTP concentrations within the cell.
View Article and Find Full Text PDFCells
December 2024
Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai 480-0392, Japan.
encodes a small GTPase of the Rho family that plays a critical role in actin cytoskeleton remodeling and intracellular signaling regulation. Pathogenic variants in , all of which reported thus far affect conserved residues within its functional domains, have been linked to neurodevelopmental disorders characterized by diverse phenotypic features, including structural brain anomalies and facial dysmorphism (NEDBAF). Recently, a novel de novo variant (NM_005052.
View Article and Find Full Text PDFUnlabelled: Biochemical interactions at membranes are the starting points for cell signaling networks. But bimolecular reaction kinetics are difficult to experimentally measure on 2-dimensional membranes and are usually measured in volumetric assays. Membrane tethering produces confinement and steric effects that will significantly impact binding rates in ways that are not readily estimated from volumetric measurements.
View Article and Find Full Text PDFPlant Physiol Biochem
November 2024
College of Agriculture, Guizhou University, Guiyang, 550025, China; Vegetable Research Academy, Guizhou University, Guiyang, 550025, China; Engineering Research Center for Protected Vegetable Crops in Higher Learning Institutions of Guizhou Province, Guiyang, 550025, China. Electronic address:
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