Objective: To investigate the effect of the leucine zipper-like motif between HRA and HRB of the human parainfluenza virus 3 fusion protein on fusion activity.
Methods: Site-directed mutagenesis was utilized to substitute the heptadic residues at 257, 264, 271, 278, 285, 292, and 299 in this motif with alanine. Additionally, 3 middle heptadic leucine residues at 271, 278, and 285 were replaced with alanine singly or in combination. A vaccinia virus-T7 RNA polymerase transient expression system was employed to express the wild-type or mutated fusion (F) proteins. Three different types of membrane fusion assays were performed to analyze the fusogenic activity, fluorescence-activated cell sorting (FACS) analysis was executed to examine the cell surface expression level, and a coimmunoprecipitation assay was conducted to probe the hemagglutinin-neuraminidase (HN)-F interaction at the cell surface.
Results: All of the substitutions in this motif exhibited diminished or even lost fusion activity in all stages of fusion, although they all had no effect on cell surface expression. In the coimmunoprecipitation assay, all mutants resulted in decreased detection of the HN-F complexes compared with that of the wild-type F protein.
Conclusions: This motif has an important influence on fusion activity, and its integrality is indispensable for membrane fusion.
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http://dx.doi.org/10.1159/000441978 | DOI Listing |
Cureus
December 2024
Ophthalmology Examination Department, Sakoh Eye Clinic, Kawasaki, JPN.
We present three cases where traditional occlusion therapy with an eye patch proved ineffective for treating amblyopia associated with fusion maldevelopment nystagmus. In these cases, we transitioned to dichoptic therapy using the Occlu-pad, achieving successful outcomes. Eye patch occlusion of the sound eye consistently exacerbated nystagmus, whereas dichoptic treatment did not.
View Article and Find Full Text PDFCureus
December 2024
Neurological Surgery, Cleveland Clinic Foundation, Cleveland, USA.
Traumatic burst fractures of the atlas occur with axial loading of the cervical spine. Many of these injuries can be treated by nonsurgical management with external orthosis; however, cases with transverse ligament disruption or significant C1 lateral mass displacement require internal reduction and fixation. In patients with poor bone quality in the setting of osteoporosis or chronic illness, atlanto-axial fixation and reduction of the fracture can be a challenge, necessitating extension of fusion to the occiput, which significantly limits the range of motion.
View Article and Find Full Text PDFNat Commun
January 2025
School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China.
Autophagy, a conserved catabolic process implicated in a diverse array of human diseases, requires efficient fusion between autophagosomes and lysosomes to function effectively. Recently, SNAP47 has been identified as a key component of the dual-purpose SNARE complex mediating autophagosome-lysosome fusion in both bulk and selective autophagy. However, the spatiotemporal regulatory mechanisms of this SNARE complex remain unknown.
View Article and Find Full Text PDFPhys Biol
January 2025
Department of Biological Sciences, Tata Institute of Fundamental Research Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha road, Navy Nagar, Colaba, Mumbai-400005, INDIA, Mumbai, 400005, INDIA.
Tracking and motion analyses of semi-flexible biopolymer networks from time-lapse microscopy images are important tools that enable quantitative measurements to unravel the dynamic and mechanical properties of biopolymers in living tissues, crucial for understanding their organization and function. Biopolymer networks are challenging to track due to continuous stochastic transitions, such as merges and splits, which cause local neighbourhood rearrangements over short time and length scales. To address this, we propose the STIPS algorithm (Spatio Temporal Information on Pixel Subsets) to track these events by creating pixel subsets that link trajectories across frames.
View Article and Find Full Text PDFJ Interferon Cytokine Res
January 2025
The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.
Suppressor of cytokine signaling (SOCS) 1 is a key negative regulator of interferon (IFN), interleukin (IL)12, and IL-2 family cytokine signaling through inhibition of the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway. To investigate the temporal induction of SOCS1 in response to cytokine in live cells and its selective regulation of signaling pathways, we generated a mouse expressing a Halo-tag-SOCS1 fusion protein (Halo-SOCS1) under control of the endogenous promoter. Homozygous Halo-SOCS1 mice () were viable with minor T cell abnormalities, most likely due to enhanced Halo-SOCS1 expression in thymocytes compared with the untagged protein.
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