A composition-dependent molecular clutch between T cell signaling condensates and actin
- Marine Biological Laboratory, United States
- University of Texas Southwestern Medical Center, United States
Abstract
During T cell activation, biomolecular condensates form at the immunological synapse (IS) through multivalency-driven phase separation of LAT, Grb2, Sos1, SLP-76, Nck, and WASP. These condensates move radially at the IS, traversing successive radially-oriented and concentric actin networks. To understand this movement, we biochemically reconstituted LAT condensates with actomyosin filaments. We found that basic regions of Nck and N-WASP/WASP promote association and co-movement of LAT condensates with actin, indicating conversion of weak individual affinities to high collective affinity upon phase separation. Condensates lacking these components were propelled differently, without strong actin adhesion. In cells, LAT condensates lost Nck as radial actin transitioned to the concentric network, and engineered condensates constitutively binding actin moved aberrantly. Our data show that Nck and WASP form a clutch between LAT condensates and actin in vitro and suggest that compositional changes may enable condensate movement by distinct actin networks in different regions of the IS.
Data availability
Data are available in the BioStudies database (http://www.ebi.ac.uk/biostudies) under accession number S-BIAD6. Image data are available in the Image Data Resource (IDR) (https://idr.openmicroscopy.org) under accession number idr0055. Condensate analysis code is available on GitHub at https://github.com/kjaqaman/CondensateAnalysis. Colocalization analysis code is available on GitHub at https://github.com/kjaqaman/ColocPt2Cont. Cluster tracking analysis code is available on GitHub at https://github.com/DanuserLab/u-track. Polarization microscopy analysis code is available on GitHub at https://github.com/mattersoflight/Instantaneous-PolScope.
Article and author information
Author details
Darius Vasco Köster
Funding
Howard Hughes Medical Institute
- Ronald D Vale
- Michael K Rosen
Cancer Research Institute
- Xiaolei Su
National Institutes of Health (R35 GM119619)
- Khuloud Jaqaman
National Institutes of Health (F32 DK101188)
- Jonathon A Ditlev
Welch Foundation (I-1544)
- Michael K Rosen
Department of Science and Technology, Government of India (J C Bose Fellowship)
- Satyajit Mayor
Margadarshi Fellowship from the Wellcome Trust - Department of Biotechnology, India Alliance (IA/M/15/1/502018)
- Satyajit Mayor
National Institutes of Health (R01 GM100160)
- Tomomi Tani
UT Southwestern Endowed Scholars Program
- Khuloud Jaqaman
National Research Service Award F32 (F32 DK101188)
- Jonathon A Ditlev
CPRIT Training Grant (RP140110 PI: Michael White)
- Anthony R Vega
AXA Research Fund and the National Centre for Biological Sciences, Tata Institute for Fundamental Research
- Darius Vasco Köster
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2019, Ditlev 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
-
- 5,186
- views
-
- 862
- downloads
-
- 94
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
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)
A composition-dependent molecular clutch between T cell signaling condensates and actin
eLife 8:e42695.
https://doi.org/10.7554/eLife.42695
Further reading
-
- Biochemistry and Chemical Biology
N 6,2’-O-dimethyladenosine (m6Am) is a modified nucleotide located at the first transcribed position in mRNA and snRNA that is essential for diverse physiological processes. m6Am mapping methods assume each gene uses a single start nucleotide. However, gene transcription usually involves multiple start sites, generating numerous 5’ isoforms. Thus, gene-level annotations cannot capture the diversity of m6Am modification in the transcriptome. Here, we describe CROWN-seq, which simultaneously identifies transcription-start nucleotides and quantifies m6Am stoichiometry for each 5’ isoform that initiates with adenosine. Using CROWN-seq, we map the m6Am landscape in nine human cell lines. Our findings reveal that m6Am is nearly always a high stoichiometry modification, with only a small subset of cellular mRNAs showing lower m6Am stoichiometry. We find that m6Am is associated with increased transcript expression and provide evidence that m6Am may be linked to transcription initiation associated with specific promoter sequences and initiation mechanisms. These data suggest a potential new function for m6Am in influencing transcription.
-
- Biochemistry and Chemical Biology
- Microbiology and Infectious Disease
Glutamine synthetases (GS) are central enzymes essential for the nitrogen metabolism across all domains of life. Consequently, they have been extensively studied for more than half a century. Based on the ATP-dependent ammonium assimilation generating glutamine, GS expression and activity are strictly regulated in all organisms. In the methanogenic archaeon Methanosarcina mazei, it has been shown that the metabolite 2-oxoglutarate (2-OG) directly induces the GS activity. Besides, modulation of the activity by interaction with small proteins (GlnK1 and sP26) has been reported. Here, we show that the strong activation of M. mazei GS (GlnA1) by 2-OG is based on the 2-OG dependent dodecamer assembly of GlnA1 by using mass photometry (MP) and single particle cryo-electron microscopy (cryo-EM) analysis of purified strep-tagged GlnA1. The dodecamer assembly from dimers occurred without any detectable intermediate oligomeric state and was not affected in the presence of GlnK1. The 2.39 Å cryo-EM structure of the dodecameric complex in the presence of 12.5 mM 2-OG demonstrated that 2-OG is binding between two monomers. Thereby, 2-OG appears to induce the dodecameric assembly in a cooperative way. Furthermore, the active site is primed by an allosteric interaction cascade caused by 2-OG-binding towards an adaption of an open active state conformation. In the presence of additional glutamine, strong feedback inhibition of GS activity was observed. Since glutamine dependent disassembly of the dodecamer was excluded by MP, feedback inhibition most likely relies on the binding of glutamine to the catalytic site. Based on our findings, we propose that under nitrogen limitation the induction of M. mazei GS into a catalytically active dodecamer is not affected by GlnK1 and crucially depends on the presence of 2-OG.
