INS and metabolic dysfunction-associated steatotic liver disease: Based on our earlier mechanistic studies in cultured hepatocytes, which suggest a role for MST4 in the regulation of hepatocellular lipotoxicity in vitro, we here applied the genetic models of whole-body and liver-specific Mst4 knockout mice to investigate the potential in vivo function of this kinase in the diet-induced impairment of systemic glucose and insulin homeostasis as well as MASLD susceptibility.