A yeast mitochondrial outer membrane protein essential for protein import and cell viability

The gene encoding ISP42, an integral outermembrane protein located at the yeast mitochondrial protein import site was cloned, sequenced and modified. Yeast cells depleted of ISP42 accumulate uncleaved mitochondrial precursor proteins and then die. ISP42 is the first mitochondrial membrane protein shown to be indispensable for protein import and cell viability.