Fzo1p is a mitochondrial outer membrane protein essential for the biogenesis of functional mitochondria in Saccharomyces cerevisiae.

Fzo1p is a novel component required for the biogenesis of functional mitochondria in the yeast Saccharomyces cerevisiae. The protein is homologous to Drosophila Fzo, the first known protein mediator of mitochondrial fusion. Deletion of the FZO1 gene results in a petite phenotype, loss of mitochondrial DNA, and a fragmented mitochondrial morphology. Fzo1p is an integral protein of the mitochondrial outer membrane exposing its major part to the cytosol. It is imported into the outer membrane in a receptor-dependent manner. Fzo1p is part of a larger protein complex of 800 kDa, and presumably is the first identified component of the yeast mitochondrial fusion machinery.