Journal: Autophagy
Article Title: Autophagy suppression via SRC induction represents a therapeutic vulnerability for BAP1 -mutant cancers
doi: 10.1080/15548627.2025.2535265
Figure Lengend Snippet: SRC binds to and phosphorylates BECN1 to regulate autophagy and proliferation. (A) BECN1 immunoprecipitation (IP) in UMRC-6 cells that overexpress SRC -V5 or an empty vector control (EV), containing plasmids for either constitutive SRC knockdown (sh SRC ) or a scrambled control (shSc). The arrow indicates the SRC -V5 band, and the bands below correspond to the heavy chain of IgG. (B) SRC -V5 was immunoprecipitated from UMRC-6 cells that overexpress SRC -V5 and were transfected with FLAG-BECN1 (or the corresponding empty vector control). (C) BECN1 (or IgG control) IP of UMRC-6 cells, followed by western blot analysis of phosphorylated tyrosine residues. (D) BECN1 IP of UMRC-6 cells overexpressing SRC -V5 (or empty vector control, EV) along with BAP1 (or EV) treated with 1 µM dasatinib for 24 h or DMSO control (vehicle). Red arrows indicate the bands for phosphorylated BECN1 (top) and VPS34 (bottom). (E,F) in vitro kinase assays of FLAG-BECN1 (or vector control) using in vitro transcribed/translated HA-SRC (E) or a kinase-dead version (F). The arrows in (E) indicate IgG heavy chains and the red asterisks (*) indicate the phosphorylated (top) and total (bottom) BECN1. (G-K) UMRC-6 cells stably expressing wild-type (WT) FLAG-BECN1, tyrosine phosphorylation mutants (non-phosphorylatable [BECN1 Y229/233/352F, BECN1-3F] or phospho-mimetic [BECN1 Y229/233/352E, BECN1-3E]) or an empty vector control (EV) were analyzed for autophagic flux by the number of GFP-LC3 puncta (G,H), the number of autolysosomes and autophagosomes (I), western blotting (J) or cell proliferation by Hoechst staining of the nuclei (K). Baf A1, 100 nM Bafilomycin A1 for 3 h; IP, immunoprecipitation; WCL, whole cell lysate. Error bars represent the average ± SE ( n = 50). n.s ., non-significant; *, p < 0.05; ***, p < 0.001 by t -tests. Non-overlapping letters represent significant differences ( p < 0.05) by ANOVA and Student-Newman-Keuls test. Scale bar: 20 μm.
Article Snippet: The ccRCC cell line with wild-type BAP1 , 786–0, was purchased from ATCC (CRL-1932).
Techniques: Immunoprecipitation, Plasmid Preparation, Control, Knockdown, Transfection, Western Blot, In Vitro, Stable Transfection, Expressing, Phospho-proteomics, Staining