Rlf is a guanine nucleotide exchange factor for the small G-proteins RalA and RalB and couples Ras- to Ral-signalling. Here the crystal structure of the catalytic module of Rlf consisting of a REM- and a CDC25-homology domain is determined. The structure is distinguished by an extended three stranded β-sheet called the flagpole. The flagpole is a conserved element in the RalGDS family of guanine nucleotide exchange factors and stabilises the orientation of the REM-domain relative to the CDC25-homology domain. A proline-rich sequence in the flagpole is unique to Rlf and several proteins that interact with this sequence by SH3 domains are identified. Conformational pre-selection results in a gain of affinity and contributes to the establishment of SH3 domain selectivity.
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http://dx.doi.org/10.1016/j.jsb.2013.07.009 | DOI Listing |
Virus Evol
November 2024
Faculty of Health Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada.
Hypermutated proviruses, which arise in a single Human Immunodeficiency Virus (HIV) replication cycle when host antiviral APOBEC3 proteins introduce extensive guanine to adenine mutations throughout the viral genome, persist in all people living with HIV receiving antiretroviral therapy (ART). However, hypermutated sequences are routinely excluded from phylogenetic trees because their extensive mutations complicate phylogenetic inference, and as a result, we know relatively little about their within-host evolutionary origins and dynamics. Using >1400 longitudinal single-genome-amplified HIV sequences isolated from six women over a median of 18 years of follow-up-including plasma HIV RNA sequences collected over a median of 9 years between seroconversion and ART initiation, and >500 proviruses isolated over a median of 9 years on ART-we evaluated three approaches for masking hypermutation in nucleotide alignments.
View Article and Find Full Text PDFAnim Cells Syst (Seoul)
January 2025
School of Biological Sciences, Seoul National University, Seoul, Republic of Korea.
βPix is a guanine nucleotide exchange factor for the Rac1 and Cdc42 small GTPases, which play important roles in dendritic spine morphogenesis by modulating actin cytoskeleton organization. The formation and plasticity of the dendritic spines are essential for normal brain function. Among the alternatively spliced βPix isoforms, βPix-b and βPix-d are expressed specifically in neurons.
View Article and Find Full Text PDFIn motoneurons, spatiotemporal dendritic patterns are established in the ventral nerve cord. While many guidance cues have been identified, the mechanisms of temporal regulation remain unknown. Previously, we identified the actin modulator Cdc42 GTPase as a key factor in this process.
View Article and Find Full Text PDFOpen Heart
January 2025
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan.
Background: The role of cyclic guanosine 3',5'-monophosphate (cGMP) after acute myocardial infarction (AMI) is not well understood despite its significance as a second messenger of natriuretic peptides (NPs) in cardiovascular disease. We investigated the association between the NP-cGMP cascade and left ventricular reverse remodelling (LVRR) in anterior AMI.
Methods: 67 patients with their first anterior AMI (median age, 64 years; male, 76%) underwent prospective evaluation of plasma concentrations of the molecular forms of A-type and B-type natriuretic peptide (BNP) and cGMP from immediately after primary percutaneous coronary intervention (PPCI) to 10 months post-AMI.
Int J Mol Sci
January 2025
Department of Animal Experimentation, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra P.O. Box LG581, Ghana.
Cisplatin is a common and highly effective chemotherapeutic agent whose nephrotoxic side effect is well-characterized. Sodium thiosulfate (STS), an FDA-approved hydrogen sulfide (HS) donor drug, is emerging as a chemoprotective agent against cisplatin-induced nephrotoxicity (CIN). In this study, we investigated the chemoprotective mechanism of STS in a rat model of CIN.
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