eprintid: 10147988 rev_number: 7 eprint_status: archive userid: 699 dir: disk0/10/14/79/88 datestamp: 2022-05-09 11:43:58 lastmod: 2022-05-09 11:43:58 status_changed: 2022-05-09 11:43:58 type: article metadata_visibility: show sword_depositor: 699 creators_name: Lee, Jaewoong creators_name: Robinson, Mark E creators_name: Ma, Ning creators_name: Artadji, Dewan creators_name: Ahmed, Mohamed A creators_name: Xiao, Gang creators_name: Sadras, Teresa creators_name: Deb, Gauri creators_name: Winchester, Janet creators_name: Cosgun, Kadriye Nehir creators_name: Geng, Huimin creators_name: Chan, Lai N creators_name: Kume, Kohei creators_name: Miettinen, Teemu P creators_name: Zhang, Ye creators_name: Nix, Matthew A creators_name: Klemm, Lars creators_name: Chen, Chun Wei creators_name: Chen, Jianjun creators_name: Khairnar, Vishal creators_name: Wiita, Arun P creators_name: Thomas-Tikhonenko, Andrei creators_name: Farzan, Michael creators_name: Jung, Jae U creators_name: Weinstock, David M creators_name: Manalis, Scott R creators_name: Diamond, Michael S creators_name: Vaidehi, Nagarajan creators_name: Muschen, Markus title: IFITM3 functions as a PIP3 scaffold to amplify PI3K signalling in B cells ispublished: pub divisions: C08 divisions: D77 divisions: B02 divisions: UCL note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher's terms and conditions. abstract: Interferon-induced transmembrane protein 3 (IFITM3) has previously been identified as an endosomal protein that blocks viral infection1,2,3. Here we studied clinical cohorts of patients with B cell leukaemia and lymphoma, and identified IFITM3 as a strong predictor of poor outcome. In normal resting B cells, IFITM3 was minimally expressed and mainly localized in endosomes. However, engagement of the B cell receptor (BCR) induced both expression of IFITM3 and phosphorylation of this protein at Tyr20, which resulted in the accumulation of IFITM3 at the cell surface. In B cell leukaemia, oncogenic kinases phosphorylate IFITM3 at Tyr20, which causes constitutive localization of this protein at the plasma membrane. In a mouse model, Ifitm3−/− naive B cells developed in normal numbers; however, the formation of germinal centres and the production of antigen-specific antibodies were compromised. Oncogenes that induce the development of leukaemia and lymphoma did not transform Ifitm3−/− B cells. Conversely, the phosphomimetic IFITM3(Y20E) mutant induced oncogenic PI3K signalling and initiated the transformation of premalignant B cells. Mechanistic experiments revealed that IFITM3 functions as a PIP3 scaffold and central amplifier of PI3K signalling. The amplification of PI3K signals depends on IFITM3 using two lysine residues (Lys83 and Lys104) in its conserved intracellular loop as a scaffold for the accumulation of PIP3. In Ifitm3−/− B cells, lipid rafts were depleted of PIP3, which resulted in the defective expression of over 60 lipid-raft-associated surface receptors, and impaired BCR signalling and cellular adhesion. We conclude that the phosphorylation of IFITM3 that occurs after B cells encounter antigen induces a dynamic switch from antiviral effector functions in endosomes to a PI3K amplification loop at the cell surface. IFITM3-dependent amplification of PI3K signalling, which in part acts downstream of the BCR, is critical for the rapid expansion of B cells with high affinity to antigen. In addition, multiple oncogenes depend on IFITM3 to assemble PIP3-dependent signalling complexes and amplify PI3K signalling for malignant transformation. date: 2020-12-17 date_type: published publisher: NATURE RESEARCH official_url: https://doi.org/10.1038/s41586-020-2884-6 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1827266 doi: 10.1038/s41586-020-2884-6 medium: Print-Electronic pii: 10.1038/s41586-020-2884-6 lyricists_name: Miettinen, Teemu lyricists_id: TPMIE59 actors_name: Flynn, Bernadette actors_id: BFFLY94 actors_role: owner funding_acknowledgements: R35CA197628 [NIH/NCI]; R01CA157644 [NIH/NCI]; R01CA213138 [NIH/NCI]; P01CA233412 [NIH/NCI]; MCG-18447-19 [Dr. Ralph and Marian Falk Medical Research Trust]; MCL-7000-18 [Leukemia and Lymphoma Society]; 5491-20 [Leukemia and Lymphoma Society]; BCDG-20327-20 [Blood Cancer Discoveries Grant]; HHMI-55108547 [Howard Hughes Medical Institute]; R35CA200422 [NIH]; R01CA251275 [NIH]; AI116585 [NIH]; AI116585S [NIH]; AI140718 [NIH]; AI140705 [NIH]; DE023926 [NIH]; DE028521 [NIH]; R01 AI104002 [NIH]; R01 AI127513 [NIH]; R01 GM117923 [NIH]; R01 GM097261 [NIH]; R35 CA231958 [NCI]; 110275/Z/15/Z [Wellcome Trust]; [Paul G. Allen Frontiers Group]; U54-CA217377 [Cancer Systems Biology Consortium from the National Cancer Institute]; U01 CA232563 [Cancer Moonshot grant]; [Alex's Lemonade Stand Foundation]; P30 CA060553 [NCI CCSG]; S10OD025194 [NIH Office of Director]; P41 GM108569 [] full_text_status: public publication: Nature volume: 588 number: 7838 pagerange: 491-497 pages: 27 event_location: England citation: Lee, Jaewoong; Robinson, Mark E; Ma, Ning; Artadji, Dewan; Ahmed, Mohamed A; Xiao, Gang; Sadras, Teresa; ... Muschen, Markus; + view all <#> Lee, Jaewoong; Robinson, Mark E; Ma, Ning; Artadji, Dewan; Ahmed, Mohamed A; Xiao, Gang; Sadras, Teresa; Deb, Gauri; Winchester, Janet; Cosgun, Kadriye Nehir; Geng, Huimin; Chan, Lai N; Kume, Kohei; Miettinen, Teemu P; Zhang, Ye; Nix, Matthew A; Klemm, Lars; Chen, Chun Wei; Chen, Jianjun; Khairnar, Vishal; Wiita, Arun P; Thomas-Tikhonenko, Andrei; Farzan, Michael; Jung, Jae U; Weinstock, David M; Manalis, Scott R; Diamond, Michael S; Vaidehi, Nagarajan; Muschen, Markus; - view fewer <#> (2020) IFITM3 functions as a PIP3 scaffold to amplify PI3K signalling in B cells. Nature , 588 (7838) pp. 491-497. 10.1038/s41586-020-2884-6 <https://doi.org/10.1038/s41586-020-2884-6>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10147988/1/nihms-1620516.pdf