1. Biochemistry and Chemical Biology
  2. Neuroscience

A model for regulation by SynGAP-α1 of binding of synaptic proteins to PDZ-domain 'Slots' in the postsynaptic density

  1. Ward G Walkup
  2. Tara L Mastro
  3. Leslie T Schenker
  4. Jost Vielmetter
  5. Rebecca Hu
  6. Ariella Iancu
  7. Meera Reghunathan
  8. Barry Dylan Bannon
  9. Mary B Kennedy  Is a corresponding author
  1. California Institute of Technology, United States
https://doi.org/10.7554/eLife.16813
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  1. Ward G Walkup
  2. Tara L Mastro
  3. Leslie T Schenker
  4. Jost Vielmetter
  5. Rebecca Hu
  6. Ariella Iancu
  7. Meera Reghunathan
  8. Barry Dylan Bannon
  9. Mary B Kennedy
(2016)
A model for regulation by SynGAP-α1 of binding of synaptic proteins to PDZ-domain 'Slots' in the postsynaptic density
eLife 5:e16813.
https://doi.org/10.7554/eLife.16813
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Abstract

SynGAP is a Ras/Rap GTPase-activating protein (GAP) that is a major constituent of postsynaptic densities (PSDs) from mammalian forebrain. Its α1 isoform binds to all three PDZ (PSD-95, Discs-large, ZO-1) domains of PSD-95, the principal PSD scaffold, and can occupy as many as 15% of these PDZ domains. We present evidence that synGAP-α1 regulates the composition of the PSD by restricting binding to the PDZ domains of PSD-95. We show that phosphorylation by Ca2+/calmodulin-dependent protein kinase II (CaMKII) and Polo-like kinase-2 (PLK2) decreases its affinity for the PDZ domains by several fold, which would free PDZ domains for occupancy by other proteins. Finally, we show that three critical postsynaptic signaling proteins that bind to the PDZ domains of PSD-95 are present in higher concentration in PSDs isolated from mice with a heterozygous deletion of synGAP.

Article and author information

Author details

  1. Ward G Walkup

    Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
    Competing interests
    No competing interests declared.

  2. Tara L Mastro

    Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
    Competing interests
    No competing interests declared.

  3. Leslie T Schenker

    Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
    Competing interests
    No competing interests declared.

  4. Jost Vielmetter

    Beckman Institute Protein Expression Center, California Institute of Technology, Pasadena, United States
    Competing interests
    No competing interests declared.

  5. Rebecca Hu

    Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
    Competing interests
    No competing interests declared.

  6. Ariella Iancu

    Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
    Competing interests
    No competing interests declared.

  7. Meera Reghunathan

    Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
    Competing interests
    No competing interests declared.

  8. Barry Dylan Bannon

    Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
    Competing interests
    No competing interests declared.

  9. Mary B Kennedy

    Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
    For correspondence
    kennedym@its.caltech.edu
    Competing interests
    Mary B Kennedy, Reviewing Editor, eLife.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-1369-0525

Funding

National Science Foundation (2006019582)

  • Ward G Walkup

National Institutes of Health (NRSA T32 GM07616)

  • Ward G Walkup

Gordon and Betty Moore Foundation (Center for Integrative Study of Cell Regulation)

  • Mary B Kennedy

Hicks Foundation

  • Mary B Kennedy

Allen and Lenabelle Davis Foundation (Endowed Chair)

  • Mary B Kennedy

National Institutes of Health (MH095095)

  • Mary B Kennedy

The Beckman Institute (Protein Expression Center)

  • Jost Vielmetter

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Leslie C Griffith, Brandeis University, United States

Ethics

Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All of the animals were handled according to approved institutional animal care and use committee (IACUC) protocol (#1034-15G) of the California Institute of Technology.

Version history

  1. Received: April 8, 2016
  2. Accepted: September 9, 2016
  3. Accepted Manuscript published: September 13, 2016 (version 1)
  4. Version of Record published: September 28, 2016 (version 2)
  5. Version of Record updated: October 19, 2016 (version 3)

Copyright

© 2016, Walkup et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Ward G Walkup
  2. Tara L Mastro
  3. Leslie T Schenker
  4. Jost Vielmetter
  5. Rebecca Hu
  6. Ariella Iancu
  7. Meera Reghunathan
  8. Barry Dylan Bannon
  9. Mary B Kennedy
(2016)
A model for regulation by SynGAP-α1 of binding of synaptic proteins to PDZ-domain 'Slots' in the postsynaptic density
eLife 5:e16813.
https://doi.org/10.7554/eLife.16813

Share this article

https://doi.org/10.7554/eLife.16813

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Further reading

    1. Biochemistry and Chemical Biology
    2. Neuroscience

    A sex difference in the response of the rodent postsynaptic density to synGAP haploinsufficiency

    Tara L Mastro, Anthony Preza ... Mary B Kennedy
    Research Advance Updated

    SynGAP is a postsynaptic density (PSD) protein that binds to PDZ domains of the scaffold protein PSD-95. We previously reported that heterozygous deletion of Syngap1 in mice is correlated with increased steady-state levels of other key PSD proteins that bind PSD-95, although the level of PSD-95 remains constant (Walkup et al., 2016). For example, the ratio to PSD-95 of Transmembrane AMPA-Receptor-associated Proteins (TARPs), which mediate binding of AMPA-type glutamate receptors to PSD-95, was increased in young Syngap1+/-mice. Here we show that only females and not males show a highly significant correlation between an increase in TARP and a decrease in synGAP in the PSDs of Syngap1+/-rodents. The data reveal a sex difference in the adaptation of the PSD scaffold to synGAP haploinsufficiency.

    1. Biochemistry and Chemical Biology

    Uncovering the BIN1-SH3 interactome underpinning centronuclear myopathy

    Boglarka Zambo, Evelina Edelweiss ... Gergo Gogl
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    Truncation of the protein-protein interaction SH3 domain of the membrane remodeling Bridging Integrator 1 (BIN1, Amphiphysin 2) protein leads to centronuclear myopathy. Here, we assessed the impact of a set of naturally observed, previously uncharacterized BIN1 SH3 domain variants using conventional in vitro and cell-based assays monitoring the BIN1 interaction with dynamin 2 (DNM2) and identified potentially harmful ones that can be also tentatively connected to neuromuscular disorders. However, SH3 domains are typically promiscuous and it is expected that other, so far unknown partners of BIN1 exist besides DNM2, that also participate in the development of centronuclear myopathy. In order to shed light on these other relevant interaction partners and to get a holistic picture of the pathomechanism behind BIN1 SH3 domain variants, we used affinity interactomics. We identified hundreds of new BIN1 interaction partners proteome-wide, among which many appear to participate in cell division, suggesting a critical role of BIN1 in the regulation of mitosis. Finally, we show that the identified BIN1 mutations indeed cause proteome-wide affinity perturbation, signifying the importance of employing unbiased affinity interactomic approaches.