Mitochondrial GTPase%2C present in complex with Ugo1p and Fzo1p%3B required for mitochondrial morphology%2C fusion%2C and genome maintenance%3B promotes membrane bending%3B exists as long and short form with different distributions%3B ratio of long to short forms is regulated by Psd1p%3B homolog of human OPA1 involved in autosomal dominant optic atrophy