Engagement of the T-cell antigen receptor leads to recruitment of phospholipase Cgamma1 (PLCgamma1) to the LAT-nucleated signaling complex and to PLCgamma1 activation in a tyrosine phosphorylation-dependent manner. The mechanism of PLCgamma1 recruitment and the role of PLCgamma1 Src homology (SH) domains in this process remain incompletely understood. Using a combination of biochemical methods and real-time fluorescent imaging, we show here that the N-terminal SH2 domain of PLCgamma1 is necessary but not sufficient for its recruitment. Either the SH3 or C-terminal SH2 domain of PLCgamma1, with the participation of Vav1, c-Cbl and Slp76, are required to stabilize PLCgamma1 recruitment. All three PLCgamma1 SH domains are required for phosphorylation of PLCgamma1 Y783, which is critical for enzyme activation. These novel findings entailed revision of the currently accepted model of PLCgamma1 recruitment and activation in T lymphocytes.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1383559 | PMC |
| http://dx.doi.org/10.1038/sj.emboj.7600978 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Membrane-bound Merkel cell polyomavirus middle T protein constitutively activates PLCγ1 signaling through Src-family kinases.
Proc Natl Acad Sci U S A
December 2023
Cancer Virology Program, Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213.
Merkel cell polyomavirus (MCV or MCPyV) is an alphapolyomavirus causing human Merkel cell carcinoma and encodes four tumor (T) antigen proteins: large T (LT), small tumor (sT), 57 kT, and middle T (MT)/alternate LT open reading frame proteins. We show that MCV MT is generated as multiple isoforms through internal methionine translational initiation that insert into membrane lipid rafts. The membrane-localized MCV MT oligomerizes and promiscuously binds to lipid raft-associated Src family kinases (SFKs).
View Article and Find Full Text PDFDiscrete LAT condensates encode antigen information from single pMHC:TCR binding events.
Nat Commun
December 2022
Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA.
LAT assembly into a two-dimensional protein condensate is a prominent feature of antigen discrimination by T cells. Here, we use single-molecule imaging techniques to resolve the spatial position and temporal duration of each pMHC:TCR molecular binding event while simultaneously monitoring LAT condensation at the membrane. An individual binding event is sufficient to trigger a LAT condensate, which is self-limiting, and neither its size nor lifetime is correlated with the duration of the originating pMHC:TCR binding event.
View Article and Find Full Text PDFDynamics of allosteric regulation of the phospholipase C-γ isozymes upon recruitment to membranes.
Elife
June 2022
Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, United States.
Numerous receptor tyrosine kinases and immune receptors activate phospholipase C-γ (PLC-γ) isozymes at membranes to control diverse cellular processes including phagocytosis, migration, proliferation, and differentiation. The molecular details of this process are not well understood. Using hydrogen-deuterium exchange mass spectrometry, we show that PLC-γ1 is relatively inert to lipid vesicles that contain its substrate, phosphatidylinositol 4,5-bisphosphate (PIP), unless first bound to the kinase domain of the fibroblast growth factor receptor (FGFR1).
View Article and Find Full Text PDFReceptor tyrosine kinases regulate signal transduction through a liquid-liquid phase separated state.
Mol Cell
March 2022
School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK. Electronic address:
The recruitment of signaling proteins into activated receptor tyrosine kinases (RTKs) to produce rapid, high-fidelity downstream response is exposed to the ambiguity of random diffusion to the target site. Liquid-liquid phase separation (LLPS) overcomes this by providing elevated, localized concentrations of the required proteins while impeding competitor ligands. Here, we show a subset of phosphorylation-dependent RTK-mediated LLPS states.
View Article and Find Full Text PDFIn vitro reconstitution reveals cooperative mechanisms of adapter protein-mediated activation of phospholipase C-γ1 in T cells.
J Biol Chem
March 2022
Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA. Electronic address:
Activation of T cells upon engagement of the T cell antigen receptor rapidly leads to a number of phosphorylation and plasma membrane recruitment events. For example, translocation of phospholipase-Cγ1 (PLC-γ1) to the plasma membrane and its association with the transmembrane adapter protein LAT and two other adapter proteins, Gads and SLP-76, are critical events in the early T cell activation process. We have previously characterized the formation of a tetrameric LAT-Gads-SLP-76-PLC-γ1 complex by reconstitution in vitro and have also characterized the thermodynamics of tetramer formation.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!