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In Vitro SUMOylation Assay to Study SUMO E3 Ligase Activity
Published on: January 29, 2018
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Tomosyn interacts with the SUMO E3 ligase PIASγ
Cornelia J Geerts1, Linda Jacobsen1, Rhea van de Bospoort1
1Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, Netherlands.
Plos One
|March 12, 2014
Summary
Tomosyn-1 interacts with PIASγ, a SUMO E3 ligase, revealing a new mechanism for regulating neurotransmission. This SUMOylation process adapts synaptic strength to neuronal activity.
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Biology
Background:
- Small Ubiquitin-like MOdifier (SUMO) conjugation regulates critical neuronal functions like synaptogenesis and synaptic plasticity.
- Tomosyn-1, a syntaxin-binding protein 5 (STXPB5), is a key regulator of neurotransmission and one of the few identified neuronal SUMO substrate proteins.
Purpose of the Study:
- To identify novel protein interactions of tomosyn-1.
- To elucidate the mechanism by which tomosyn-1 is SUMOylated in neurons.
- To understand how SUMOylation of tomosyn-1 impacts synaptic function.
Main Methods:
- Yeast two-hybrid screening to identify protein interactors.
- Co-immunoprecipitation assays to confirm protein interactions.
- Expression of full-length proteins in HEK293T cells.
Main Results:
- Tomosyn-1 was found to interact with the SUMO E3 ligase PIASγ (PIAS4/ZMIZ6).
- The interaction occurred between the C-terminus of tomosyn-1 and the N-terminus of PIASγ.
- Tomosyn-1 was preferentially modified by the SUMO-2/3 isoform in a PIASγ-dependent manner.
Conclusions:
- A novel interaction between tomosyn-1 and PIASγ was discovered, mediated by specific protein domains.
- PIASγ-dependent SUMO-2/3 modification of tomosyn-1 provides a new regulatory mechanism for synaptic strength.
- This mechanism allows secretory strength to adapt to the dynamic synaptic environment, impacting neuronal function.
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