The role of SNAP-25 (synaptosomal associated protein of 25 kDa) isotypes in the neurotransmitter release process was examined by varying their relative abundance during PC12 cell differentiation induced by nerve growth factor (NGF). Norepinephrine release by NGF-differentiated PC12 cells is more sensitive to type A botulinum toxin (BoNT/A) than by nondifferentiated cells, while both differentiated and nondifferentiated PC12 cells are equally sensitive to type E botulinum toxin (BoNT/E). The differential sensitivity to BoNT/A corresponds to an altered susceptibility of SNAP-25 isotypes to BoNT/A cleavage in vitro, whereas both isotypes are equally vulnerable to cleavage by BoNT/E. Using recombinant SNAP-25 preparations, we show that BoNT/A cleaves SNAP-25b (present in differentiated cells) 2-fold more readily than SNAP-25a (present in both differentiated and nondifferentiated cells). Structural studies using far-ultraviolet circular dichroism (UV--CD) and thermal denaturation suggest a difference in the polypeptide folding as the underlying molecular basis for the differential sensitivity of SNAP-25b and SNAP-25a to BoNT/A cleavage. We propose differential roles for SNAP-25b and SNAP-25a in the neurotransmitter release process since our results suggest that BoNT/A inhibits neurotransmitter release by primarily cleaving SNAP-25b.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/bi010362z | DOI Listing |
Curr Pain Headache Rep
January 2025
Department of Anesthesiology, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA, 71103, USA.
Purpose Of Review: Baclofen, a muscle relaxant that reduces the release of excitatory neurotransmitters in the pre-synaptic neurons stimulating inhibitory neuronal signals in post-synaptic neurons, has been around for over 5 decades. Baclofen is used primarily for spasticity and since 1982, has had a role as an intrathecal agent. In the present investigation, we review research trends and updates on safety and efficacy of intrathecal baclofen (ITB) pumps.
View Article and Find Full Text PDFElife
January 2025
Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Cigarette smoking is a well-known risk factor inducing the development and progression of various diseases. Nicotine (NIC) is the major constituent of cigarette smoke. However, knowledge of the mechanism underlying the NIC-regulated stem cell functions is limited.
View Article and Find Full Text PDFBackground: The locus coeruleus (LC), is the first brain region to develop hyperphosphorylated tau (ptau) inclusions in Alzheimer's disease (AD) and undergoes catastrophic degeneration in later stages of the disease. Importantly, the LC is the main noradrenergic nucleus in the brain and source of NE in the forebrain, and dysregulation of the neurotransmitter norepinephrine (NE) is associated with AD symptoms, as its release in the forebrain regulates attention, arousal, stress response, and learning and memory. Moreover, the LC may transmit pathogenic tau to the forebrain via its extensive projections.
View Article and Find Full Text PDFBackground: Posttranslational modifications of tau occurs throughout disease progression in Alzheimer's disease (AD) and non-AD tauopathies. Phosphorylation of tau (p-tau) in the proline-rich region is a common target of immunohistochemical and fluid biomarker evaluation. P-tau217 has emerged as a highly accurate fluid biomarker in AD, however elevated levels are not observed in non-AD tauopathies.
View Article and Find Full Text PDFJ Appl Lab Med
January 2025
Department of Pathology, University of Iowa Health Care, Iowa City, IA, United States.
Background: Heparin-induced thrombocytopenia (HIT) is a potentially life-threatening adverse drug reaction with numerous diagnostic challenges. Diagnosis of HIT begins with 4T score clinical assessment, followed by laboratory testing for those not deemed low risk. Laboratory testing for HIT includes screening [enzyme-linked immunosorbent assay (ELISA)] and confirmatory [serotonin release assay (SRA)] assays, wherein SRA testing can be pursued following a positive ELISA result.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!