1. Biochemistry and Chemical Biology
  2. Neuroscience
Download icon

An extracellular biochemical screen reveals that FLRTs and Unc5s mediate neuronal subtype recognition in the retina

  1. Jasper J Visser
  2. Yolanda Cheng
  3. Steven C Perry
  4. Andrew Benjamin Chastain
  5. Bayan Parsa
  6. Shatha S Masri
  7. Thomas A Ray
  8. Jeremy N Kay
  9. Woj M Wojtowicz  Is a corresponding author
  1. University of California, Berkeley, United States
  2. Duke University School of Medicine, United States
  3. University of California Berkeley, United States
Research Article
  • Cited 30
  • Views 3,450
  • Annotations
Cite this article as: eLife 2015;4:e08149 doi: 10.7554/eLife.08149

Abstract

In the inner plexiform layer (IPL) of the mouse retina, ~70 neuronal subtypes organize their neurites into an intricate laminar structure that underlies visual processing. To find recognition proteins involved in lamination, we utilized microarray data from 13 subtypes to identify differentially-expressed extracellular proteins and performed a high-throughput biochemical screen. We identified ~50 previously-unknown receptor-ligand pairs, including new interactions among members of the FLRT and Unc5 families. These proteins show laminar-restricted IPL localization and induce attraction and/or repulsion of retinal neurites in culture, placing them in ideal position to mediate laminar targeting. Consistent with a repulsive role in arbor lamination, we observed complementary expression patterns for one interaction pair, FLRT2-Unc5C, in vivo. Starburst amacrine cells and their synaptic partners, ON-OFF direction-selective ganglion cells, express FLRT2 and are repelled by Unc5C. These data suggest that a single molecular mechanism may have been co-opted by synaptic partners to ensure joint laminar restriction.

Article and author information

Author details

  1. Jasper J Visser

    Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Yolanda Cheng

    Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Steven C Perry

    Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Andrew Benjamin Chastain

    Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Bayan Parsa

    Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Shatha S Masri

    Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Thomas A Ray

    Departments of Neurobiology and Opthalmology, Duke University School of Medicine, Durham, United States
    Competing interests
    The authors declare that no competing interests exist.
  8. Jeremy N Kay

    Departments of Neurobiology and Opthalmology, Duke University School of Medicine, Durham, United States
    Competing interests
    The authors declare that no competing interests exist.
  9. Woj M Wojtowicz

    Molecular and Cell Biology, University of California Berkeley, Berkeley, United States
    For correspondence
    woj.wojtowicz@gmail.com
    Competing interests
    The authors declare that no competing interests exist.

Ethics

Animal experimentation: All animal procedures were approved by the University of California, Berkeley (Office of Laboratory Animal Care (OLAC) protocol #R308) and they conformed to the National Institutes of Health Guide for the Care and Use of Laboratory Animals, the Public Health Service Policy and the Society for Neuroscience Policy on the Use of Animals in Neuroscience Research.

Reviewing Editor

  1. Constance Cepko, Harvard University, United States

Publication history

  1. Received: April 16, 2015
  2. Accepted: December 1, 2015
  3. Accepted Manuscript published: December 2, 2015 (version 1)
  4. Accepted Manuscript updated: December 10, 2015 (version 2)
  5. Version of Record published: January 22, 2016 (version 3)

Copyright

© 2015, Visser 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

  • 3,450
    Page views
  • 786
    Downloads
  • 30
    Citations

Article citation count generated by polling the highest count across the following sources: Crossref, Scopus, PubMed Central.

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)

Download citations (links to download the citations from this article in formats compatible with various reference manager tools)

Open citations (links to open the citations from this article in various online reference manager services)

Further reading

    1. Biochemistry and Chemical Biology
    Astrid Kollewe et al.
    Research Article Updated

    The transient receptor potential melastatin-subfamily member 7 (TRPM7) is a ubiquitously expressed membrane protein consisting of ion channel and protein kinase domains. TRPM7 plays a fundamental role in the cellular uptake of divalent cations such as Zn2+, Mg2+, and Ca2+, and thus shapes cellular excitability, plasticity, and metabolic activity. The molecular appearance and operation of TRPM7 channels in native tissues have remained unresolved. Here, we investigated the subunit composition of endogenous TRPM7 channels in rodent brain by multi-epitope affinity purification and high-resolution quantitative mass spectrometry (MS) analysis. We found that native TRPM7 channels are high-molecular-weight multi-protein complexes that contain the putative metal transporter proteins CNNM1-4 and a small G-protein ADP-ribosylation factor-like protein 15 (ARL15). Heterologous reconstitution experiments confirmed the formation of TRPM7/CNNM/ARL15 ternary complexes and indicated that complex formation effectively and specifically impacts TRPM7 activity. These results open up new avenues towards a mechanistic understanding of the cellular regulation and function of TRPM7 channels.

    1. Biochemistry and Chemical Biology
    2. Chromosomes and Gene Expression
    Fang Huang et al.
    Research Article

    The positive transcription elongation factor b (P-TEFb) is a critical co-activator for transcription of most cellular and viral genes, including those of HIV. While P-TEFb is regulated by 7SK snRNA in proliferating cells, P-TEFb is absent due to diminished levels of CycT1 in quiescent and terminally differentiated cells, which has remained unexplored. In these cells, we found that CycT1 not bound to CDK9 is rapidly degraded. Moreover, productive CycT1:CDK9 interactions are increased by PKC mediated phosphorylation of CycT1 in human cells. Conversely, dephosphorylation of CycT1 by PP1 reverses this process. Thus, PKC inhibitors or removal of PKC by chronic activation results in P-TEFb disassembly and CycT1 degradation. This finding not only recapitulates P-TEFb depletion in resting CD4+ T cells but also in anergic T cells. Importantly, our studies reveal mechanisms of P-TEFb inactivation underlying T cell quiescence, anergy, and exhaustion as well as proviral latency and terminally differentiated cells.