Figure 5. YIR003W (AIM21) is required for mitochondrial motility.

(A)–(B). Dual immunofluorescence of mitochondria (outer membrane protein porin stained in red) and actin (total actin, stained in green) in the indicated yeast strains (scale bar 2 µm). (C) Mitochondrial motility was measured in strains carrying an integrated mitochondrially-targeted GFP (methods) by tracking the movement of the tip of a mitochondrion within a budding cell every second for two minutes. A sustained mitochondrial movement is defined as movement in the same direction for at least three consecutive seconds. PUF3 is a gene with known involvement in mitochondrial motility [54]. To determine the frequency of sustained mitochondrial movement resulting from Brownian motion or other passive processes (methods), sustained mitochondrial movement was measured in the presence of the metabolic inhibitors sodium azide (NaN3) and sodium fluoride (NaF). 10 mM concentrations of these inhibitors were compared to a control of 10 mM sodium chloride (NaCl). Raw data are available in Table S8. Due to its lack of static actin or mitochondrial phenotypes, the motility defect in AIM21 mutants would be difficult to find without integrative computational predictions driving specific experimental assays.