The DPP4 gene encodes dipeptidyl peptidase 4, which is identical to adenosine deaminase complexing protein-2, and to the T-cell activation antigen CD26. It is an intrinsic type II transmembrane glycoprotein and a serine exopeptidase that cleaves X-proline dipeptides from the N-terminus of polypeptides. Dipeptidyl peptidase 4 is highly involved in glucose and insulin metabolism, as well as in immune regulation. This protein was shown to be a functional receptor for Middle East respiratory syndrome coronavirus (MERS-CoV), and protein modeling suggests that it may play a similar role with SARS-CoV-2, the virus responsible for COVID-19. [provided by RefSeq, Apr 2020]
Forensic Context
A study in humans identified the DPP4 as a diagnostic biomarker with higher expression in control groups compared to sepsis patients, validated through machine learning and ROC curve analysis (AUC >0.7) in transcriptomic datasets [Lu et al. DOI:10.3389/fimmu.2025.1543517]. Single-cell analysis revealed its predominant expression in CD4+ memory cells, and it was incorporated into a diagnostic nomogram demonstrating strong predictive ability (AUC >0.9), with its expression further confirmed as significantly higher in controls via RT-qPCR validation on clinical blood samples.