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Synergistic factors control kinase–phosphatase organization in B-cells engaged with supported bilayers
B-cells become activated by ligands with varying valency and mode of presentation to the B-cell receptor (BCR). We previously demonstrated that clustering the immunoglobulin M (IgM) isotype of BCR with an artificial soluble cross-linker stabilized an ordered phase-like domain that enriched kinases a...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The American Society for Cell Biology
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7202075/ https://www.ncbi.nlm.nih.gov/pubmed/31877064 http://dx.doi.org/10.1091/mbc.E19-09-0507 |
Sumario: | B-cells become activated by ligands with varying valency and mode of presentation to the B-cell receptor (BCR). We previously demonstrated that clustering the immunoglobulin M (IgM) isotype of BCR with an artificial soluble cross-linker stabilized an ordered phase-like domain that enriched kinases and depleted phosphatases to promote receptor tyrosine phosphorylation. BCR is also activated by ligands presented at surfaces, and here we activate B-cells via supported bilayers of phosphatidylcholine lipids, a natural ligand for the IgM BCR expressed in the CH27 cells used. Using superresolution fluorescence localization microscopy, along with a quantitative cross-correlation analysis, we find that BRCs engaged with bilayers sort minimal peptide markers of liquid-ordered and liquid-disordered phases, indicating that ordered-domain stabilization is a general feature of BCR clustering. The phosphatase CD45 is more strongly excluded from bilayer-engaged BRCs than a transmembrane peptide, indicating that mechanisms other than domain partitioning contribute to its organization. Experimental observations are assembled into a minimal model of receptor activation that incorporates both ordered domains and direct phosphatase exclusion mechanisms to produce a more sensitive response. |
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