Cholesterol Alters the Dynamics of Release in Protein Independent Cell Models for Exocytosis
Journal article, 2016

Neurons communicate via an essential process called exocytosis. Cholesterol, an abundant lipid in both secretory vesicles and cell plasma membrane can affect this process. In this study, amperometric recordings of vesicular dopamine release from two different artificial cell models created from a giant unilamellar liposome and a bleb cell plasma membrane, show that with higher membrane cholesterol the kinetics for vesicular release are decelerated in a concentration dependent manner. This reduction in exocytotic speed was consistent for two observed modes of exocytosis, full and partial release. Partial release events, which only occurred in the bleb cell model due to the higher tension in the system, exhibited amperometric spikes with three distinct shapes. In addition to the classic transient, some spikes displayed a current ramp or plateau following the maximum peak current. These post spike features represent neurotransmitter release from a dilated pore before constriction and show that enhancing membrane rigidity via cholesterol adds resistance to a dilated pore to re-close. This implies that the cholesterol dependent biophysical properties of the membrane directly affect the exocytosis kinetics and that membrane tension along with membrane rigidity can influence the fusion pore dynamics and stabilization which is central to regulation of neurochemical release.

membrane tension

snare proteins

individual chromaffin cells

hemifusion

lipid nanotubes

vesicles

bending elasticity

kiss-and-run

flickering fusion pores

pc12 cells

Author

Neda Najafinobar

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Lisa Mellander

University of Gothenburg

Michael Kurczy

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Johan Dunevall

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Tina B. Angerer

University of Gothenburg

John Fletcher

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Ann-Sofie Cans

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Scientific Reports

2045-2322 (ISSN) 20452322 (eISSN)

Vol. 6 Article number: 33702 33702

Subject Categories

Chemical Sciences

DOI

10.1038/srep33702

PubMed

27650365

More information

Latest update

2/6/2018 9