Fig. 7: Cdkn2a positively regulates Becn1 expression by suppressing its mRNA decay and promotes BECN1-mediated autophagy by interacting with BCL2L1.

a Immunofluorescence staining of p16^INK4a and p19^ARF distribution during beige adipocyte maintenance. b Western blot to confirm the immunoprecipitation of p16^INK4a and p19^ARF proteins. c RNA immunoprecipitation-qPCR (RIP-qPCR) analysis of the interaction of Becn1, Atg5, Atg12, Pink1 and Ucp1 transcripts with p16^INK4a in beige adipocytes (n = 3). d RNA immunoprecipitation-qPCR (RIP-qPCR) analysis of the interaction of the Becn1 transcript with p19^ARF in beige adipocytes (n = 3). e mRNA lifetimes of Becn1 and Ucp1 in control and Cdkn2a^Ucp1 KO beige adipocytes (n = 3). f Co-immunoprecipitation (Co-IP) analysis of the interaction between p19^ARF and BECN1 or BCL2L1. g Co-IP analysis of the interaction between p16^INK4a and BECN1 or BCL2L1. h Co-IP analysis of the interaction between BCL2L1 and BECN1 in control and Cdkn2a^Ucp1 KO beige adipocytes after withdrawing external stimuli (n = 3). Quantification of the BECN1/BCL2L1 ratio in the IP samples is shown in the right panel. i Working model. In wild type cells, p16^INK4a specifically targets Becn1 mRNA and increases its expression by promoting mRNA stability, while p19^ARF interacts with BCL2L1 and releases BECN1, thereby enhancing autophagy and beige-to-white transition. Loss of Cdkn2a decreases the protein levels of p16^INK4a and p19^ARF, resulting in reduced expression and activity of BECN1, thereby inhibiting autophagy and promoting beige fat maintenance. p values were determined by two-tailed Student’s t test. Data are expressed as means ± SEM.