Endogenous sterol biosynthesis is important for mitochondrial function and cell morphology in procyclic forms of Trypanosoma brucei

► The biological role of squalene and post-squalene metabolites has been studied in insect forms of Trypanosoma brucei. ► Depletion of these endogenous sterol metabolites results in impaired cell growth. ► Perturbation of synthesis of endogenous sterols leads to aberrant morphologies and DNA fragmentation. ► Sterol depletion results in profound modifications in mitochondrial structure and function. ► Bulk 24-alkyl sterols are not strictly required to support growth.