GFP or GFP-DRP1 was co-expressed with empty vector or those expressing ARL2 or ARL2, and mitochondrial morphologies in GFP positive cells were scored. Expression of DRP1 resulted in mitochondria with increased apparent length and interconnectivity when coexpressed with either empty vector or wild-type ARL2, compared to cells coexpressing GFP and pcDNA or wild-type ARL2. Co-expression of GFP-DRP1 reversed mitochondrial fragmentation caused by ARL2, despite the fact that ARL2 caused mitochondrial fragmentation when co-transfected with GFP alone.Cells co-transfected with GFP-DRP1 and empty vector, ARL2 wild type, or ARL2 were scored for fragmented mitochondria, and we observed no statistically significant differences. In addition to the fragmentation of mitochondria there was an increase in perinuclear clustering of mitochondria in cells Catharanthine sulfate depleted for ARL2 or expressing ARL2. This clustering was most readily seen as an absence, or clearly diminished density, of mitochondria in the cell periphery as mitochondria in control cells typically appear to have a higher density near the nucleus for a number of reasons. This perinuclear clustering with loss of peripheral mitochondria was almost completely absent in control cells but was seen in 23.760.5% of cells depleted of ARL2. In efforts to gain further insights into Aceclidine hydrochloride possible relationships between fragmentation and clustering of mitochondria we performed time-lapse imaging. Control cells, expressing only mito-GFP, were characterized by mitochondria moving in a bidirectional fashion with thread-like morphology that displayed readily observable fusion and fission events. Substantial mitochondrial fragmentation, perinuclear clustering, or sustained loss of motility were rare in controls. In contrast, cells depleted of ARL2 by siRNA displayed mitochondrial fragmentation, with or without clustering, by the end of the eight hour imaging window. Perinuclear clustering of mitochondria occurred in 1663.1% of imaged cells, resulting from directed movement of the fragmented mitochondria inward, with a near complete absence of outward movement.