Overexpression of the regulatory subunit of protein kinase A increases heterologous protein expression in Pichia pastoris

Objective Translational regulation plays an important role in protein synthesis. Our goal was to screen translation-related factors to improve heterologous protein expression in Pichia pastoris . Results Twenty-eight translation-related factors were overexpressed in P. pastoris GS115 expressing enhanced green fluorescent protein (eGFP). The results showed that overexpression of Bcy1, the regulatory subunit of protein kinase A (PKA), significantly increased both eGFP expression and cell biomass by 20% under methanol induction for 120 h. Additionally, overexpression of Bcy1 elevated the growth rate by 18% and increased production of the industrial enzyme Phytase (Phy) by 26%. Transcriptome analysis indicated that the overall expression of ribosomal protein genes was significantly downregulated and that postdiauxic shift genes and stress response element genes were upregulated. Conclusions Bcy1 regulates ribosome protein genes, postdiauxic shift genes and stress response element genes, leading to improved cell growth and heterologous protein expression. This study provides a convenient and universal factor for heterologous protein production.