GSK3B and colorectal carcinoma: However, an immunohistochemical study of colorectal carcinomas found that p-Akt(Ser473) staining correlated with phosphorylation of its downstream substrates GSK-3β and Bad, while p-Akt(Thr308) expression only correlated with phosphorylation of GSK-3β, and not that of Bad (182), perhaps suggesting substrate specific targeting.