KCMF1 promotes MASLD progression via K48-linked ubiquitination and degradation of AMPKα.

BACKGROUND/AIMS: Metabolic dysfunction-associated steatotic liver disease (MASLD) lacks effective pharmacotherapy. Although AMP-activated protein kinase (AMPK) is a central metabolic regulator with hepatoprotective effects, the upstream mechanisms governing its degradation in MASLD remain poorly defined. Here, we identify potassium channel modulatory factor 1 (KCMF1) as a previously unrecognized E3 ubiquitin ligase targeting AMPKα and investigate its role in MASLD pathogenesis.

METHODS

Protein interactions were characterized by co-immunoprecipitation and GST pull-down assays. Ubiquitin-linkage specificity and AMPKα stability were assessed biochemically. Hepatocyte-targeted gain-of-function and hepatocyte-specific KCMF1 ablation were evaluated across multiple mouse MASLD models (HFD, GAN, CDAHFD, and ob/ob), with AMPK dependency assessed by pharmacological modulation. An AI-guided virtual screen with biophysical validation was conducted to identify candidate KCMF1 inhibitors.

RESULTS

KCMF1 expression was markedly upregulated in hepatocytes from murine and human MASLD livers. KCMF1 directly interacted with AMPKα and catalyzed its K48-linked polyubiquitination, promoting its degradation and suppressing hepatic AMPK signaling. Functionally, hepatic KCMF1 overexpression exacerbated steatosis, inflammation, and fibrosis, whereas its knockdown or hepatocyte-specific deletion conferred protection across MASLD models. Pharmacological modulation of AMPK in vivo and in primary hepatocytes demonstrated pathway dependency, as AMPK activation attenuated KCMF1-driven pathology. Furthermore, the flavonoid Rhoifolin was identified as a direct KCMF1 binder that stabilized AMPKα and ameliorated MASLD in mice.

CONCLUSIONS

KCMF1 drives MASLD pathogenesis by promoting K48-linked ubiquitination and degradation of AMPKα. Targeting the KCMF1-AMPK axis restores hepatic metabolic homeostasis and represents a potential therapeutic strategy for MASLD.