Fig. 6

Impact of FACI knockout on EGF and transferrin uptake. A FACI mRNA expression intensities in various cell lines. Data were retrieved from NCBI BioProject PRJNA183192. nTPM: normalized transcripts per kilobase million. B Generation of FACI^−/− HeLa cell lines (FACI^−/−-1 & FACI^−/−-2) by CRISPR/Cas9 technique. The region closest to ATG codon of FACI (top) was targeted. gRNAs (red) and PAM sequences (yellow) were highlighted. FACI^−/− HeLa cell lines were verified with gene sequencing and representative sequencing chromatographs (middle) were shown. In FACI^−/−− 1 & FACI^−/−− 2 cells, the FACI coding regions were disrupted by frameshift and nonsense mutations (bottom). C EGF uptake in WT and FACI^−/− HeLa cells (left), and in FACI-expressed (Dox) and control (no Dox) AML12 cells (right). The amounts of endocytosed pHrodo-Red-EGF were measured by flow cytometry. The representative flow cytometric histograms and the results of quantitative analysis (n = 3 ~ 4) were indicated. Data are mean fluorescence intensity ± SD. *: P < 0.05. **: P < 0.01 by two-tailed paired Student’s t-test. D Transferrin uptake in WT and FACI^−/− HeLa cells (left), and in FACI-expressing (Dox) and control (no Dox) AML12 cells (right). The amounts of endocytosed pHrodo-Red-Transferrin were measured by flow cytometry. The representative flow cytometric histograms and the results of quantitative analysis (n = 3 ~ 4) were indicated. Data are mean fluorescence intensity ± SD