Abstract
Successful B cell activation, which is critical for high-affinity antibody production, is controlled by the B cell antigen receptor (BCR). However, we still lack a comprehensive protein-level view of the very dynamic multi-branched cellular events triggered by antigen binding. Here, we employed APEX2 proximity biotinylation to study antigen-induced changes, 5–15 min after receptor activation, at the vicinity of the plasma membrane lipid rafts, wherein BCR enriches upon activation. The data reveals dynamics of signaling proteins, as well as various players linked to the subsequent processes, such as actin cytoskeleton remodeling and endocytosis. Interestingly, our differential expression analysis identified dynamic responses in various proteins previously not linked to early B cell activation. We demonstrate active SUMOylation at the sites of BCR activation in various conditions and report its functional role in BCR signaling through the AKT and ERK1/2 axes.
| Original language | English |
|---|---|
| Article number | jcs261119 |
| Number of pages | 18 |
| Journal | Journal of Cell Science |
| Volume | 136 |
| Issue number | 15 |
| DOIs | |
| Publication status | Published - Aug 2023 |
| MoE publication type | A1 Journal article-refereed |
Funding
This work was supported by the Academy of Finland (grant ID: 25700, 296684, 307313 and 339810 to P.K.M.; 286712 to V.Š .; 337530 to InFLAMES), and the foundations of Sigrid Jusélius (Sigrid Juséliuksen Säätiö) and Jane and Aatos Erkko (Jane ja Aatos Erkon Säätiö) (to P.K.M.), Magnus Ehrnrooth (Magnus Ehrnroothin Säätiö) (to P.K.M., L.O.A and A.V.S.) and University of Turku Foundation (Turun Yliopisto säätiö) (to L.O.A., M.R. and S.H.-P.), as well as Finnish Cultural foundation (Suomen Kulttuurirahasto) (to S.H.-P. and V.Š .) and Turku Doctoral Programme in Molecular Medicine (TuDMM) (to L.O.A., D.M.C., M.R. and S.H.-P.). Open Access funding provided by University of Turku. Deposited in PMC for immediate release. We thank Laura Grönfors, Johanna Rajala and Citarra Burrows for technical help and Dr Maria Sundvall for her generous help regarding sumoylation reagents. MS analysis was performed at the Turku Bioscience Proteomics Facility, where Anne Rokka and the other staff is acknowledged for their help. Microscopy and flow cytometry were performed at Turku Bioscience Cell Imaging and Cytometry (CIC) core, supported by Turku Bioimaging and Euro-Bioimaging, whose personnel is thanked for their generous help and expertise. Biocenter Finland and the InFLAMES Flagship Programme of the Academy of Finland are acknowledged for providing research infrastructures. This work was supported by the Academy of Finland (grant ID: 25700, 296684, 307313 and 339810 to P.K.M.; 286712 to V.Š.; 337530 to InFLAMES), and the foundations of Sigrid Jusélius (Sigrid Juséliuksen Säätiö) and Jane and Aatos Erkko (Jane ja Aatos Erkon Säätiö) (to P.K.M.), Magnus Ehrnrooth (Magnus Ehrnroothin Säätiö) (to P.K.M., L.O.A and A.V.S.) and University of Turku Foundation (Turun Yliopisto säätiö) (to L.O.A., M.R. and S.H.-P.), as well as Finnish Cultural foundation (Suomen Kulttuurirahasto) (to S.H.-P. and V.Š.) and Turku Doctoral Programme in Molecular Medicine (TuDMM) (to L.O.A., D.M.C., M.R. and S.H.-P.). Open Access funding provided by University of Turku. Deposited in PMC for immediate release.
Keywords
- APEX2
- B cells
- BCR signaling
- Golga3
- Lipid rafts
- SUMOylation