elongation, constriction, and fission. Translocation of dynamin-like protein 1 
(DLP1), a member of the large GTPase family, from the cytosol to peroxisomes is 
a prerequisite for membrane fission; however, the molecular machinery for 
peroxisomal targeting of DLP1 remains unclear. This study investigated whether 
mitochondrial fission factor (Mff), which targets DLP1 to mitochondria, may also 
recruit DLP1 to peroxisomes. Results show that endogenous Mff is localized to 
peroxisomes, especially at the membrane-constricted regions of elongated 
peroxisomes, in addition to mitochondria. Knockdown of MFF abrogates the fission 
stage of peroxisomal division and is associated with failure to recruit DLP1 to 
peroxisomes, while ectopic expression of MFF increases the peroxisomal targeting 
of DLP1. Co-expression of MFF and PEX11β, the latter being a key player in 
peroxisomal elongation, increases peroxisome abundance. Overexpression of MFF 
also increases the interaction between DLP1 and Pex11pβ, which knockdown of MFF, 
but not Fis1, abolishes. Moreover, results show that Pex11pβ interacts with Mff 
in a DLP1-dependent manner. In conclusion, Mff contributes to the peroxisomal 
targeting of DLP1 and plays a key role in the fission of the peroxisomal 
membrane by acting in concert with Pex11pβ and DLP1.