AKT1 and rheumatoid arthritis: All three peptidesubstrate reporters tested were initially developed and validatedin human cell lines.12,23,25−27 Applications of these peptide substrate reportershave involved patient cells and mammalian cell lines for pancreaticcancer28 and rheumatoid arthritis.29 While previous work has focused on the roleof PKB in human health, the PI3K-PKB pathway is integral to cell stressresponse in many organisms.