Ubiquitination of P53 by E3 ligase MKRN2 promotes melanoma cell proliferation.

Melanoma is the most aggressive and lethal type of skin cancer. The aim of the present study was to illustrate the molecular mechanism of makorin ring finger protein 2 (MKRN2) control of melanoma cell proliferation. The expression level of MKRN2 was detected in human malignant melanoma cell lines by immunoblotting and reverse transcription-quantitative PCR. Short hairpin RNAs for MKRN2 were designed and transfected into melanoma cells, and the proliferation of these cells was detected by MTT and colony formation assays. The interaction of MKRN2 with P53 was detected by co-immunoprecipitation and glutathione S-transferase pulldown assays. The ubiquitination of P53 by MKRN2 was detected by in vitro ubiquitination assays. A P53-knockout cell line was generated using the CRISPR-Cas9 method. MKRN2 exhibited higher expression levels in melanoma cells, and downregulation of MKRN2 inhibited melanoma cell growth in a P53-dependent manner. MKRN2 regulated melanoma cell proliferation by interacting and ubiquitylating P53, which suggests that MKRN2 may be a potential therapeutic target for melanoma.