Fig. 1.

Polypyrimidine tract binding protein 1 (PTBP1) may interact with alpha actinin-4 (ACTN4) in gastric cancer (GC) cells. (A) Screening of PTBP1 interacting proteins in AGS cells using co-immunoprecipitation-mass spectrometry (Co-IP-MS). (B) 217 proteins were identified, of which 41 were identified by two samples simultaneously. The number of unique proteins identified by IP and IgG was 164 and 12, respectively. (C) The proteins are identified by comparing with the Cluster of Orthologous Groups (COG) database, and their functional classification are predicted through statistical analysis. Identification results were compared to the statistical map of the COG database. The abscissa represents the number of proteins, and the ordinate represents the annotated COG entries. (D) The Gene Expression Profiling Interactive Analysis (GEPIA) website was used to analyse the Cancer Genome Atlas (TCGA) database for data on patients with GC. (E) The possible downstream target genes of PTBP1 were predicted by QIAGEN protein database analysis. (F) Co-IP assay confirmed that PTBP1 protein binds to ACTN4 protein. (G) RNA binding protein immunoprecipitation (RIP) assay confirmed that PTBP1 protein binds to ACTN4 RNA. (H) Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the changes in ACTN4 after PTBP1 knockdown in GC cells. (I) The protein-protein interaction figure was generated using PyMOL. ^∗P < 0.05 and ^∗∗P < 0.01. M: marker; TPM: transcripts per million; STAD: stomach adenocarcinoma; CK19: cytokeratin 19; TPM3: tropomyosin 3; MYH9: non-muscle myosin heavy chain IIA; MYH14: myosin heavy chain 14; VIL1: villin 1; MYO1D: myosin 1D; K17: keratin 17; MYO1C: myosin 1C; CTTN: cortactin; shNC: short hairpin negative control; NLS: nuclear localization signal; NES: nuclear export signal; RRM: RNA recognition motif.