IQ-ArfGEF/BRAG1, a guanine nucleotide exchange factor for Arf1 and Arf6, is localized at the postsynaptic density (PSD) and interacts with PSD-95. In this study, we identified a novel interaction of IQ-ArfGEF/BRAG1 with insulin receptor tyrosine kinase substrate of 53 kDa (IRSp53), also known as brain-specific angiogenesis inhibitor 1-associated protein 2. The interaction was mediated by the binding of the C-terminal proline-rich sequence of IQ-ArfGEF/BRAG1 to the SH3 domain of IRSp53. IQ-ArfGEF/BRAG1 and IRSp53 were colocalized at the PSD of excitatory synapses of certain neuronal populations. Our present findings suggest that IQ-ArfGEF/BRAG1 may play roles downstream of NMDA receptors through the interaction with multivalent PSD proteins such as IRSp53 and PSD-95.
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http://dx.doi.org/10.1016/j.brainres.2008.11.061 | DOI Listing |
Unlabelled: SYNGAP1 is a key Ras-GAP protein enriched at excitatory synapses, with mutations causing intellectual disability and epilepsy in humans. Recent studies have revealed that in addition to its role as a negative regulator of G-protein signaling through its GAP enzymatic activity, SYNGAP1 plays an important structural role through its interaction with post-synaptic density proteins. Here, we reveal that intrinsic excitability deficits and seizure phenotypes in heterozygous Syngap1 knockout (KO) mice are differentially dependent on Syngap1 GAP activity.
View Article and Find Full Text PDFJ Biol Chem
January 2025
Division of Regulatory Glycobiology, Graduate School of Pharmaceutical Sciences, Tohoku Medical and Pharmaceutical University; Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai, Miyagi 981-8558, Japan. Electronic address:
Core fucosylation is one of the most essential modifications of the N-glycans, catalyzed by α1,6-fucosyltransferase (Fut8), which transfers fucose from guanosine 5'-diphosphate (GDP)-fucose to the innermost N-acetylglucosamine residue of N-glycans in an α1-6 linkage. Our previous studies demonstrated that lipopolysaccharide (LPS) can induce a more robust neuroinflammatory response in Fut8 homozygous knockout (KO) (Fut8) and heterozygous KO (Fut8) mice contrasted to the wild-type (Fut8) mice. Exogenous administration of L-fucose suppressed LPS-induced neuroinflammation.
View Article and Find Full Text PDFJ Neuroinflammation
January 2025
Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.
The brain presents various structural and functional sex differences, for which multiple factors are attributed: genetic, epigenetic, metabolic, and hormonal. While biological sex is determined by both sex chromosomes and sex hormones, little is known about how these two factors interact to establish this dimorphism. Sex differences in the brain also affect its resident immune cells, microglia, which actively survey the brain parenchyma and interact with sex hormones throughout life.
View Article and Find Full Text PDFNeurobiol Dis
January 2025
Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada. Electronic address:
The consequences of non-pathogenic huntingtin (HTT) reduction in the mature brain are of substantial importance as clinical trials for numerous HTT-lowering therapies are underway; many of which are non-selective in that they reduce both mutant and wild type protein variants. In this study, we injected CaMKII-promoted AAV-Cre directly into the hippocampus of adult HTT floxed mice to explore the role of wild-type huntingtin (wtHTT) in adult hippocampal pyramidal neurons and the broader implications of its loss. Our findings reveal that wtHTT depletion results in profound macroscopic morphological abnormalities in hippocampal structure, accompanied by significant reactive gliosis.
View Article and Find Full Text PDFTzu Chi Med J
August 2024
Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan.
Schizophrenia (SCZ) is a chronic psychotic disorder that profoundly alters an individual's perception of reality, resulting in abnormal behavior, cognitive deficits, thought distortions, and disorientation in emotions. Many complicated factors can lead to SCZ, and investigations are ongoing to understand the neurobiological underpinnings of this condition. Presynaptic Netrin G1 and its cognate partner postsynaptic Netrin-G-Ligand-1 (NGL-1) have been implicated in SCZ.
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