Changes in corticotrope gene expression upon increased expression of peptidylglycine a-amidating monooxygenase, an evolutionarily conserved enzyme

Throughout evolution, secretion has played an essential role in the ability of organisms and single cells to survive in the face of a changing environment. PAM (peptidylglycine a-amidating monooxygenase) is an integral membrane monooxygenase first identified for its role in the biosynthesis of neuroendocrine peptides released by the regulated secretory pathway. By screening for transcripts whose expression in a corticotrope tumor cell line responded to changes in PAM levels, we sought to identify genes not previously known to play a role in secretion. We identified transcription factors, peptidyl prolyl isomerases, endosomal/lysosomal proteins and proteins involved in tissue-specific responses to glucose and amino acid availability that had not previously been recognized as participants in secretion. Examination of mRNA profiles in corticotropes expressing basal or induced levels of PAM, followed by quantitative PCR and Western blot analyses.