Dilation of fusion pores by crowding of SNARE proteins

• Autores: Wu, Zhenyong; Bello, Oscar Daniel; Thiyagarajan, Sathish; Auclair, Sarah Marie; Vennekate, Wensi; Krishnakumar, Shyam S; O'Shaughnessy, Ben; Karatekin, Erdem
• Año de publicación: 2017
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: E. COLI; SNARE PROTEINS; BIOPHYSICS; CELL BIOLOGY; EXOCYTOSIS; FUSION PORE; MEMBRANE FUSION; PROTEIN CROWDING; STRUCTURAL BIOLOGY
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Hormones and neurotransmitters are released through fluctuating exocytotic fusion pores that can flicker open and shut multiple times. Cargo release and vesicle recycling depend on the fate of the pore, which may reseal or dilate irreversibly. Pore nucleation requires zippering between vesicle-associated v-SNAREs and target membrane t-SNAREs, but the mechanisms governing the subsequent pore dilation are not understood. Here, we probed the dilation of single fusion pores using v-SNARE-reconstituted ~23-nm-diameter discoidal nanolipoprotein particles (vNLPs) as fusion partners with cells ectopically expressing cognate, ’flipped’ t-SNAREs. Pore nucleation required a minimum of two v-SNAREs per NLP face, and further increases in v-SNARE copy numbers did not affect nucleation rate. By contrast, the probability of pore dilation increased with increasing v-SNARE copies and was far from saturating at 15 v-SNARE copies per face, the NLP capacity. Our experimental and computational results suggest that SNARE availability may be pivotal in determining whether neurotransmitters or hormones are released through a transient (’kiss and run’) or an irreversibly dilating pore (full fusion).
Fil: Wu, Zhenyong. University of Yale; Estados Unidos. University of Yale. School of Medicine; Estados Unidos
Fil: Bello, Oscar Daniel. University of Yale. School of Medicine; Estados Unidos. University of Yale; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina
Fil: Thiyagarajan, Sathish. Columbia University; Estados Unidos
Fil: Auclair, Sarah Marie. University of Yale. School of Medicine; Estados Unidos. University of Yale; Estados Unidos
Fil: Vennekate, Wensi. University of Yale; Estados Unidos. University of Yale. School of Medicine; Estados Unidos
Fil: Krishnakumar, Shyam S. University of Yale; Estados Unidos. University of Yale. School of Medicine; Estados Unidos
Fil: O'Shaughnessy, Ben. Columbia University; Estados Unidos
Fil: Karatekin, Erdem. University of Yale; Estados Unidos. Universite Paris Descartes; Francia. University of Yale. School of Medicine; Estados Unidos