MKRN2 (makorin ring finger protein 2) is an E3 ubiquitin ligase that plays crucial roles in inflammatory regulation, tumor suppression, and male fertility. Its primary function involves catalyzing the ubiquitination and subsequent proteasomal degradation of key regulatory proteins 12. The protein employs diverse mechanisms to regulate cellular processes: it selectively inhibits IL-6 translation by ubiquitinating PAIP1, thereby disrupting PAIP1-eIF4A interactions and blocking IL-6 mRNA translation 1. MKRN2 also targets NF-κB p65 for degradation, suppressing inflammatory signaling pathways 3, and promotes ubiquitination of IGF2BP3 in neuroblastoma cells 2. In cancer contexts, MKRN2 functions as a tumor suppressor through multiple pathways, including destabilization of PPP2CA proteins leading to Wnt pathway inactivation in renal cell carcinoma 4, and regulation of tumor microenvironment by controlling macrophage polarization 3. MKRN2 is frequently downregulated in human malignancies through promoter hypermethylation and miRNA-mediated suppression, correlating with advanced disease stage and poor survival 3. Additionally, MKRN2 is essential for male fertility, as knockout mice exhibit infertility associated with decreased STAT1, SIX4, and TNC expression 5. The protein's diverse substrate specificity and multi-pathway regulation establish it as a critical regulator of inflammation, tumorigenesis, and reproduction 6.