γ-Protocadherin structural diversity and functional implications
- Columbia University, United States
Abstract
Stochastic cell-surface expression of α-, β-, and γ-clustered protocadherins (Pcdhs) provides vertebrate neurons with single-cell identities that underlie neuronal self-recognition. Here we report crystal structures of ectodomain fragments comprising cell-cell recognition regions of mouse γ-Pcdhs γA1, γA8, γB2, and γB7 revealing trans-homodimers, and of C-terminal ectodomain fragments from γ-Pcdhs γA4 and γB2, which depict cis-interacting regions in monomeric form. Together these structures span the entire Pcdhγ ectodomain. The trans-dimer structures reveal determinants of Pcdh-γ isoform-specific homophilic recognition. We identified and structurally mapped cis-dimerization mutations to the C-terminal ectodomain structures. Biophysical studies showed that Pcdh ectodomains from γB-subfamily isoforms formed cis dimers, whereas γA isoforms did not, but both γA and γB isoforms could interact in cis with α-Pcdhs. Together, these data show how interaction specificity is distributed over all domains of the γ-Pcdh trans interface, and suggest that subfamily- or isoform-specific cis-interactions may play a role in the Pcdh-mediated neuronal self-recognition code.
Data availability
-
Protocadherin gamma A1 extracellular cadherin domains 1-4Publicly available at the RCSB Protein Data Bank (accession no. 5SZL).
-
Protocadherin gamma A8 extracellular cadherin domains 1-4Publicly available at the RCSB Protein Data Bank (accession no. 5SZM).
-
Protocadherin gamma A9 extracellular cadherin domains 1-5Publicly available at the RCSB Protein Data Bank (accession no. 5SZN).
-
Protocadherin Gamma B7 extracellular cadherin domains 1-4 P41212 crystal formPublicly available at the RCSB Protein Data Bank (accession no. 5SZO).
-
Protocadherin Gamma B7 extracellular cadherin domains 1-4 P21 crystal formPublicly available at the RCSB Protein Data Bank (accession no. 5SZP).
-
Protocadherin gamma A4 extracellular cadherin domains 3-6Publicly available at the RCSB Protein Data Bank (accession no. 5SZQ).
-
Protocadherin Gamma B2 extracellular cadherin domains 3-6Publicly available at the RCSB Protein Data Bank (accession no. 5SZR).
-
Protocadherin Gamma B2 extracellular cadherin domains 1-5Publicly available at the RCSB Protein Data Bank (accession no. 5T9T).
-
Structure of mouse clustered PcdhgA1 EC1-3Publicly available at the RCSB Protein Data Bank (accession no. 4ZI9).
-
Crystal Structure of Protocadherin Gamma A8 EC1-3Publicly available at the RCSB Protein Data Bank (accession no. 4ZPS).
-
Protocadherin alpha 7 extracellular cadherin domains 1-5Publicly available at the RCSB Protein Data Bank (accession no. 5DZV).
Article and author information
Author details
Funding
National Institutes of Health (R01GM107571)
- Tom Maniatis
- Lawrence Shapiro
Howard Hughes Medical Institute (R01GM062270)
- Fabiana Bahna
- Barry Honig
National Science Foundation (MCB-1412472)
- Barry Honig
Howard Hughes Medical Institute
- Fabiana Bahna
- Göran Ahlsén
- Barry Honig
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- William I Weis, Stanford University Medical Center, United States
Version history
- Received: August 23, 2016
- Accepted: October 6, 2016
- Accepted Manuscript published: October 26, 2016 (version 1)
- Version of Record published: November 11, 2016 (version 2)
Copyright
© 2016, Goodman 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.
Metrics
-
- 2,105
- Page views
-
- 463
- Downloads
-
- 38
- Citations
Article citation count generated by polling the highest count across the following sources: Crossref, PubMed Central, Scopus.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
γ-Protocadherin structural diversity and functional implications
eLife 5:e20930.
https://doi.org/10.7554/eLife.20930
Further reading
-
- Cell Biology
- Structural Biology and Molecular Biophysics
The Endosomal Sorting Complexes Required for Transport (ESCRT) machinery mediates the membrane fission step that completes cytokinetic abscission and separates dividing cells. Filaments composed of ESCRT-III subunits constrict membranes of the intercellular bridge midbody to the abscission point. These filaments also bind and recruit cofactors whose activities help execute abscission and/or delay abscission timing in response to mitotic errors via the NoCut/Abscission checkpoint. We previously showed that the ESCRT-III subunit IST1 binds the cysteine protease CAPN7 (Calpain-7) and that CAPN7 is required for both efficient abscission and NoCut checkpoint maintenance (Wenzel et al., 2022). Here, we report biochemical and crystallographic studies showing that the tandem MIT domains of CAPN7 bind simultaneously to two distinct IST1 MIT interaction motifs. Structure-guided point mutations in either CAPN7 MIT domain disrupted IST1 binding in vitro and in cells, and depletion/rescue experiments showed that the CAPN7-IST1 interaction is required for: 1) CAPN7 recruitment to midbodies, 2) efficient abscission, and 3) NoCut checkpoint arrest. CAPN7 proteolytic activity is also required for abscission and checkpoint maintenance. Hence, IST1 recruits CAPN7 to midbodies, where its proteolytic activity is required to regulate and complete abscission.
-
- Biochemistry and Chemical Biology
- Structural Biology and Molecular Biophysics
The seventh pandemic of the diarrheal cholera disease, which began in 1960, is caused by the Gram-negative bacterium Vibrio cholerae. Its environmental persistence provoking recurring sudden outbreaks is enabled by V. cholerae's rapid adaption to changing environments involving sensory proteins like ToxR and ToxS. Located at the inner membrane, ToxR and ToxS react to environmental stimuli like bile acid, thereby inducing survival strategies e.g. bile resistance and virulence regulation. The presented crystal structure of the sensory domains of ToxR and ToxS in combination with multiple bile acid interaction studies, reveals that a bile binding pocket of ToxS is only properly folded upon binding to ToxR. Our data proposes an interdependent functionality between ToxR transcriptional activity and ToxS sensory function. These findings support the previously suggested link between ToxRS and VtrAC-like co-component systems. Besides VtrAC, ToxRS is now the only experimentally determined structure within this recently defined superfamily, further emphasizing its significance. In-depth analysis of the ToxRS complex reveals its remarkable conservation across various Vibrio species, underlining the significance of conserved residues in the ToxS barrel and the more diverse ToxR sensory domain. Unravelling the intricate mechanisms governing ToxRS's environmental sensing capabilities, provides a promising tool for disruption of this vital interaction, ultimately inhibiting Vibrio's survival and virulence. Our findings hold far-reaching implications for all Vibrio strains that rely on the ToxRS system as a shared sensory cornerstone for adapting to their surroundings.
