The roles of Ptpn22 Ser452 phosphorylation in tumor-infiltrating CD8+ T cells from mouse

Protein Tyrosine Phosphatase Non-receptor type 22 (PTPN22) is encoded by a major autoimmunity gene and is a known inhibitor of T cell receptor (TCR) signaling for cancer immunotherapy. However, little is known about PTPN22 phosphorylation in tumor infiltrating T cells. Here we characterize a phosphorylation site at Ser452 situated in the interdomain of PTPN22, and its roles in altering T cell function and tumor growth. Tumor infiltrating CD8+ T cells from PepWT or PepS452A mice were collected and subjected to next-generation sequencing (NGS). The results revealed it differentially regulates the genes expression of metabolic process, cytokine prodcution and adaptive immunity etc. This study explores the function of a novel phosphorylation site of PTPN22 that is involved in complex regulation of CD8+ T cell activity, fuctions and tumor growth. MC38 tumor cells were injected into PepWT or PepS425A mice and tumors were collected after 18days and digested by collagenase to get the single cell suspensions. CD8+ T cells were sorted out by cell sortor and used for bulk RNA sequencing,