Abstract：Objective To analyze the structure and function of human prostate-associated gene 4 (PAGE4) by bioinformatics software. Methods The physicochemical properties of PAGE4 were analyzed by the ProtParam tool. The phosphorylation,glycosylation and mutation sites of PAGE4 were predicted by NetPhos 3.1 Server, NetOGlyc 4.0 Server, NetNGlyc 1.0 Server and cBioPortal database. The transmembrane region, signal peptide, and subcellular localization of PAGE4 protein were predicted by TMHMM Server 2.0, SignalP 5.0 Server, and PSORT Ⅱ Prediction, respectively. The protein domain of PAGE4 was analyzed by SOPMA, SWISS-MODEL and DisProt. Online databases such as STRING, Target Scan, miRDB, and DIANA-microT were used to predict the interacting proteins of PAGE4 and the potential upstream microRNAs. Results The bioinformatics analysis showed that the molecular formula of PAGE4 was C459H743N147O171S3, the molecular weight was 11,153.01, and PAGE4 contained 102 amino acids. PAGE4 was a hydrophilic protein, which was localized in cells. It was a non-secretory protein without a transmembrane region and signal peptide. There was a nuclear localization signal in the protein sequence. Subcellular localization analysis displayed that PAGE4 was mainly located in mitochondria, cytoskeleton, and nucleus. PAGE4 had 10 phosphorylation sites, but no glycosylation site was found. The secondary structure of PAGE4 was mainly irregular curl, and there was no tertiary structure in PAGE4. PAGE4 protein disorder was about 100%, which was a natural disorder protein. PAGE4 had a potential interaction with 10 molecules such as homeodomain-interacting protein kinase 1 (HIPK1) and dual specificity protein kinase (CLK2). hsa-miR-371a-5p, hsa-miR-6505-3p, hsa-miR-3919, hsa-miR-3123 and hsa-miR-4704-3p might regulate the expression of PAGE4. Conclusion PAGE4 is a hydrophilic, disordered and non-secretory intracellular protein with phosphorylation sites and mutation sites, which can interact with a variety of proteins and microRNAs. Analyzing the structural and functional characteristics of PAGE4 can provide a theoretical basis for the in-depth study of biological function and pathogenic molecular mechanism of PAGE4.
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