Biophysical Society Conference | Estes Park 2023

Membrane Budding and Fusion

Wednesday Speaker Abstracts

DIFFERENTIAL CO-RELEASE OF CATECHOLAMINE AND ATP FROM A VESICLE FUSION PORE IN MOUSE ADRENAL CHROMAFFIN CELLS

Zhuan Zhou 1 ; Qianfeng Zhang 1 ; 1 Peking University, Beijing, China

Co-release of multiple neurotransmitters from secretory vesicles is common in neurons and neuroendocrine cells. However, whether and how the transmitters co-released from a single vesicle are differentially regulated remain unknown. In matrix containing dense-core vesicles (DCVs) in chromaffin cells, there are two modes of catecholamine (CA) release from a single DCV: quantal and sub-quantal. By combining two microelectrodes of a Carbon Fiber Electrochemical (CFE) and a “ATP sniffer” electrode to simultaneously record co-release of the native CA and ATP from a DCV, we report that (1) CA and ATP were co-released during a DCV fusion; (2) during kissand-run (KAR) fusion, the co-released CA was subquantal, whereas the co-released ATP was quantal; and (3) knockdown and knockout of the DCV matrix led to quantal co-release of both CA and ATP even in KAR mode. These findings indicate that, in contrast to the sub-quantal CA release in chromaffin cells, a fast synaptic transmission without transmitter-matrix binding is probably exclusively via a full synaptic quantal release.

AGGREGATION-DEPENDENT LIPID/FUSION PEPTIDES PORE FORMATION, AND MICROVESICLES THAT SECRETE EXOSOMES Joshua Zimmerberg ; 1 National Institutes of Health, Bethesda, MD, USA No Abstract

46