A new member of the dynamin superfamily modulates mitochondrial membrane branching in Trypanosoma brucei
Description
In contrast to most eukaryotes, where mitochondria continuously undergo fusion and fission, trypanosome cells maintain a single, interconnected mitochondrial network that divides only during cytokinesis. However, the mechanisms underlying mitochondrial remodeling and interconnection in trypanosomes remain largely unknown. Here, we characterize a new member of the dynamin-superfamily protein (DSP) from Trypanosoma brucei (TbMfnL), which shares similarities with homologs found across various eukaryotic and prokaryotic phyla but is absent in opisthokonts such as mammals and budding yeast. TbMfnL possesses a distinct sequence and domain organization and is phylogenetically distant from yeast and mammalian dynamin-related proteins involved in mitochondrial fusion and fission, such as Opa1 and Mfn. TbMfnL localizes to the inner mitochondrial membrane, facing the matrix, and its overexpression leads to a significant increase in mitochondrial interconnection and branching in a GTPase-dependent manner. These findings suggest that TbMfnL is a key component of a previously uncharacterized membrane remodeling machinery with a unique matrix-side localization, capable of modulating intermitochondrial connectivity.