Purification of rat adrenocortical actin and its use in an immunoprecipitation assay to quantitate cellular actin

Abstract

In an earlier study on the long-term effects of the pituitary hormone corticotropin (adrenocorticotropin, ACTH), we reported that ACTH promotes the loss of 20-25% of the total actin in isolated rat adrenocortical cells [1]. In a continuation of this work, we report here the purification to near homogeneity of rat adrenal actin. We demonstrate that the protein purified is adrenal actin, and use this actin in the DNAase immunoprecipitation assay of Snabes et al. [2] to confirm our earlier observation of the effect of ACTH on adrenocortical actin. Finally, we describe several changes made in the original protocol of this immunoassay which we believe significantly improve the accuracy of the assay in estimating actin contents in tissue and cell samples.