Exo-endocytosis and closing of the fission pore during endocytosis in single pituitary nerve terminals internally perfused with high calcium concentrations - PubMed (original) (raw)

Exo-endocytosis and closing of the fission pore during endocytosis in single pituitary nerve terminals internally perfused with high calcium concentrations

H Rosenboom et al. Proc Natl Acad Sci U S A. 1994.

Abstract

An increase in free Ca2+ triggers exocytosis in pituitary nerve terminals leading to an increase in membrane area and membrane capacitance. When Ca2+ is increased by step depolarization, an instantaneous capacitance increase during the first 80 ms is followed by a slow increase extending over several seconds. We measured capacitance changes associated with exocytosis and endocytosis in single pituitary nerve terminals internally perfused with high Ca2+. At 50 microM Ca2+ the capacitance increased by up to 2%/s, similar to the slow phase observed during depolarization. Our results indicate that at the site of fusion very high Ca2+ is required. Following exocytosis, large downward capacitance steps were measured, reflecting endocytosis of large vacuoles. These events were not abrupt but reflected a gradual decrease of fission pore conductance from 8 nS to < 40 pS during 500 ms, revealing the dynamics of individual fission pore closures. Above 300 pS, narrowing of the endocytotic fission pore was approximately 10 times slower than the previously reported expansion of the exocytotic fusion pore. The transition between 300 pS and 0 pS took approximately 200 ms, whereas it has been reported that the exocytotic fusion pore measured in mast cells opens from 0 to 280 pS in < 100 microseconds. The time course of closing of the fission pore may be explained by an exponential decrease in pore diameter occurring at a constant rate.

PubMed Disclaimer

Cited by

Shape bistability of a membrane neck: a toggle switch to control vesicle content release.
Frolov VA, Lizunov VA, Dunina-Barkovskaya AY, Samsonov AV, Zimmerberg J. Frolov VA, et al. Proc Natl Acad Sci U S A. 2003 Jul 22;100(15):8698-703. doi: 10.1073/pnas.1432962100. Epub 2003 Jul 11. Proc Natl Acad Sci U S A. 2003. PMID: 12857952 Free PMC article.
Membrane fusion protein synexin (annexin VII) as a Ca2+/GTP sensor in exocytotic secretion.
Caohuy H, Srivastava M, Pollard HB. Caohuy H, et al. Proc Natl Acad Sci U S A. 1996 Oct 1;93(20):10797-802. doi: 10.1073/pnas.93.20.10797. Proc Natl Acad Sci U S A. 1996. PMID: 8855260 Free PMC article.
Methods for cell-attached capacitance measurements in mouse adrenal chromaffin cell.
Varga KT, Jiang Z, Gong LW. Varga KT, et al. J Vis Exp. 2014 Oct 22;(92):e52024. doi: 10.3791/52024. J Vis Exp. 2014. PMID: 25408421 Free PMC article.
Vesicle formation by self-assembly of membrane-bound matrix proteins into a fluidlike budding domain.
Shnyrova AV, Ayllon J, Mikhalyov II, Villar E, Zimmerberg J, Frolov VA. Shnyrova AV, et al. J Cell Biol. 2007 Nov 19;179(4):627-33. doi: 10.1083/jcb.200705062. J Cell Biol. 2007. PMID: 18025300 Free PMC article.
Reconstitution and real-time quantification of membrane remodeling by single proteins and protein complexes.
Bashkirov PV, Kuzmin PI, Chekashkina K, Arrasate P, Vera Lillo J, Shnyrova AV, Frolov VA. Bashkirov PV, et al. Nat Protoc. 2020 Aug;15(8):2443-2469. doi: 10.1038/s41596-020-0337-1. Epub 2020 Jun 26. Nat Protoc. 2020. PMID: 32591769 Free PMC article.

References

1. J Cell Biol. 1973 May;57(2):315-44 - PubMed
1. Biosci Rep. 1992 Dec;12(6):495-501 - PubMed
1. J Anat. 1977 Feb;123(Pt 1):213-8 - PubMed
1. Physiol Rev. 1980 Apr;60(2):396-441 - PubMed
1. J Cell Biol. 1981 Mar;88(3):564-80 - PubMed

Exo-endocytosis and closing of the fission pore during endocytosis in single pituitary nerve terminals internally perfused with high calcium concentrations - PubMed (original) (raw)