Extended Data Fig. 9: KIDINS220 is a unique partner protein of the XPR1 phosphate efflux complex.
a) Genetic dependency correlations to XPR1 dependency across 851 cancer cell lines was assessed by pearson correlation test and corrected for multiple comparisons using the Benjamini-Hochberg method. Genes with significantly correlated dependency profiles are highlighted, as are proteins with known connection to XPR1 regulation. b) The viability defect of the indicated cancer cell lines after KIDINS220 inactivation was evaluated as in Fig. 1c. N = 3 technical replicates representative of at least N = 2 independent transductions per cell line. c) SLC34A2 was inactivated in EMTOKA and OVISE, and the KIDINS220 dependency was evaluated as in b. N = 3 technical replicates representative of at least N = 2 independent transductions per cell line.d) The interacting partners of XPR1 and KIDINS220 were downloaded from the BioGrid and Bioplex databases and compared. Proteins present in the XPR1 or KIDINS220 interactomes are highlighted as text.e) Left, the mRNA expression of XPR1 and KIDINS220 is shown for the fifteen tissues with the highest correlation in expression. The line represents linear regression for these samples (N = 2,799). Right, the Pearson correlation for those tissues, highlighting the diverse tissues in which there is a high correlation between XPR1 and KIDINS220 expression. f) Mutants of XPR1 used in this manuscript. XPR1 WT refers to the 696 amino acid protein produced by NM_004736 (the only isoform detected by RT-PCR of OVISE mRNA), while XPR1 (short) refers to the 631 amino acid product of NM_001135669. All constructs have C-terminal V5 tags for immunoprecipitation, western blotting, and immunofluorescent detection. g) XPR1 or Luciferase (Luc) were overexpressed in 293 T cells and immunoprecipitated using the V5 tag and analyzed by targeted immunoblot or for total protein. Proteins were extracted from this gel and identified using mass spectrometry, the results of which are shown in Fig. 6c. N = 1 replicate of N = 2 independent transfections. h) Cas9 + sgRNA targeting XPR1 or KIDINS220 were transfected into 293 T cells, and clones were isolated that lacked expression of the target proteins. For XPR1 inactivated cells, the XPR1 ORF was re-expressed, and the relative levels of the indicated proteins were detected by immunoblot. At least N = 2 clonal populations were profiled for each inactivation condition. i) Five days after infection with the indicated sgRNA targeting XPR1 or KIDINS220, free inorganic intracellular phosphate was determined as in Fig. 4d. N = 3 technical replicates of N = 3 independent transductions.
