Angiopoietin-like proteins (ANGPTLs) play major roles in the trafficking and metabolism of lipids. Angiopoietin-like protein 8 (ANGPTL8, aka betatrophin, lipasin) can regulate ANGPTL3 by binding to and promoting cleavage of it, thereby further activating ANGPTL3 (a protein that plays a critical role in the regulation of triglyceride and cholesterol plasma levels, via reversible inhibition of lipoprotein lipase activity) (Ren et al. 2012, Quagliarini et al. 2012, Li & Teng 2014). The exact mechanism of action of ANGPTL8 on ANGPTL3 is poorly understood.