Subcellular localization of a protein produced in adrenal cortex cells in response to ACTH

We have reported previously that a protein, ib, is produced in adrenal cortex and other steroidogenic cells with the same tissue-specific peptide hormone or cAMP dose-response and the same kinetics as the increase in steroid hormone biosynthesis. In this study, we have fractionated adrenal cortex cells into subcellular components and used two-dimensional electrophoresis to characterize the proteins in these fractions. We have demonstrated previously that inhibition of cytosolic translation, e.g. by cycloheximide, prevents the production of protein ib. We also report that the production of this protein is not affected by inhibition of mitochondrial translation by chloramphenicol.