Insights into the structure and molecular topography of the fatty acylated domain of synaptotagmin-1

Piotr Ruchala; Alan J Waring; Marianne Cilluffo; Julian P Whitelegge; Cameron B Gundersen

doi:10.1016/j.bbamem.2018.12.019

Insights into the structure and molecular topography of the fatty acylated domain of synaptotagmin-1

Biochim Biophys Acta Biomembr. 2019 Mar 1;1861(3):677-684. doi: 10.1016/j.bbamem.2018.12.019. Epub 2019 Jan 4.

Authors

Piotr Ruchala¹, Alan J Waring², Marianne Cilluffo³, Julian P Whitelegge⁴, Cameron B Gundersen⁵

Affiliations

¹ Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA; The Pasarow Mass Spectrometry Laboratory, The Jane and Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, UCLA, USA.
² Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA; Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA.
³ Brain Research Institute, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA.
⁴ Brain Research Institute, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA; The Pasarow Mass Spectrometry Laboratory, The Jane and Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, UCLA, USA.
⁵ Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA. Electronic address: cgundersen@mednet.ucla.edu.

PMID: 30615859
DOI: 10.1016/j.bbamem.2018.12.019

Abstract

Abundant attention has focused on synaptotagmin's C2 domains, but less is known about the structure and function of its other regions. Here, we synthesized the N-acetylated, C-end amidated and Cys-palmitated peptide (VLTCCFCICK KCLFKKKNKK K) which includes the fatty acylated cysteine residues in the membrane-affiliated domain of synaptotagmin-1. Fourier-transform infrared spectrometry indicated that this peptide's conformation is influenced by environmental polarity. In artificial bilayer membranes, this peptide exhibited abundant β-structure. Electron microscopy revealed that this peptide also promoted the stacking of liposome membranes. Together these results suggest that the fatty acylated region of synaptotagmin-1 is likely to adopt β-structure in biological membranes. This preference for β-structure versus α-helix has functional implications for the role of synaptotagmin-1 in synaptic vesicle exocytosis.

Keywords: Exocytosis; Membrane fusion; Protein palmitoylation; Secretion.

Publication types

Research Support, N.I.H., Extramural

MeSH terms

Acylation
Exocytosis / physiology
Fatty Acids / chemistry*
Fatty Acids / metabolism*
Humans
Liposomes / chemistry
Liposomes / metabolism
Mass Spectrometry
Membrane Fusion
Protein Domains
Protein Structure, Secondary / physiology
Spectroscopy, Fourier Transform Infrared
Structure-Activity Relationship
Synaptic Transmission
Synaptotagmin I / chemistry*
Synaptotagmin I / metabolism
Synaptotagmin I / physiology*

Substances

Fatty Acids
Liposomes
SYT1 protein, human
Synaptotagmin I

Grants and funding

P30 DK063491/DK/NIDDK NIH HHS/United States