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Exocrine cells utilize large secretory vesicles (LSVs) up to 10 μm in diameter. LSVs fuse with the apical surface, often recruiting actomyosin to extrude their content through dynamic fusion pores. The molecular mechanism regulating pore dynamics remains largely uncharacterized. We observe that the fusion pores of LSVs in the Drosophila larval salivary glands expand, stabilize, and constrict. Arp2/3 is essential for pore expansion and stabilization, while myosin II is essential for pore constriction. We identify several Bin-Amphiphysin-Rvs (BAR) homology domain proteins that regulate fusion pore expansion and stabilization. We show that the I-BAR protein Missing-in-Metastasis (MIM) localizes to the fusion site and is essential for pore expansion and stabilization. The MIM I-BAR domain is essential but not sufficient for localization and function. We conclude that MIM acts in concert with actin, myosin II, and additional BAR-domain proteins to control fusion pore dynamics, mediating a distinct mode of exocytosis, which facilitates actomyosin-dependent content release that maintains apical membrane homeostasis during secretion.
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http://dx.doi.org/10.1083/jcb.202302112 | DOI Listing |
Front Bioeng Biotechnol
August 2025
Department of Traditional Chinese Medicine Rehabilitation, Jiangbei Branch of The First Hospital Affiliated to Army Medical University (Third Military Medical University), Chongqing, China.
Background: Complex interbody fusion remains challenging, while traditional surgical instruments are not suitable for complex spinal deformities. Porous tantalum (Ta) has excellent osteogenic properties, but there is currently a lack of research on its application in cervical thoracic interbody fusion.
Objective: To introduce the application of selective electron beam melting (SEBM) 3D printing technology in customized porous Ta vertebral fusion implants and evaluate its mid-term clinical efficacy in complex cervical thoracic fusion surgery.
Bioessays
September 2025
Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.
The timely release of chemical messengers is a crucial step in cell-to-cell communication. Does this release occur as a passive diffusion from the donor membrane or it is actively regulated? A series of studies indicated that chemical messengers' secretion is "sub-quantal". This mode of secretion demands a strongly regulated release mechanism and calls for a thorough characterization of the release sites.
View Article and Find Full Text PDFUltrasonics
August 2025
School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore; Singapore Centre for 3D Printing (SC3DP), Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.
The designability of Laser powder bed fusion (LPBF) technology for material microstructure enables the fabrication of high-performance additive manufactured (AM) components. However, challenges remain due to inevitable pores induced by laser shock and parameter fluctuations during manufacturing, which introduce uncertainties in both porosity and microstructures. In this work, ultrasonic bulk wave is employed to evaluate porosity within the context of coupled pore-microstructure effects.
View Article and Find Full Text PDFbioRxiv
August 2025
National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bldg. 35, Rm. 2B-1012, Bethesda, MD 20892.
The ATPase N-ethylmaleimide-sensitive factor (NSF), known for disassembling SNARE complexes, plays key roles in neurotransmitter release, neurotransmitter (AMPA, GABA, dopamine) receptor trafficking, and synaptic plasticity, and its dysfunction or mutation is linked to neurological disorders. These roles are largely attributed to SNARE-mediated exocytosis. Here, we reveal a previously unrecognized role for NSF: mediating diverse modes of endocytosis-including slow, fast, ultrafast, overshoot, and bulk-by driving closure of both fusion and fission pores.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2025
School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, USA.
Uncovering the mechanisms of freezing and melting behavior in nanoconfined fluids can unlock fundamental insights into the fate and transport of fluids in soils present in cold climates. From a scientific perspective, the structural and thermodynamic behavior of confined and interfacial water has sparked significant discussions, particularly regarding the characteristics of phase transitions and spatial heterogeneity as a function of temperature and pressure. Observations frequently report interfacial unfrozen liquid layers on hydrophilic surfaces, distorted ice crystals and suppressed freezing and melting points in confined water compared to bulk water.
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