AKT1 (v-akt murine thymoma viral oncogene homolog 1) is a Ser/Thr protein kinase, and is also called protein kinase B (PKB). This protein is activated when it is phosphorylated at serine 473 and threonine 308. This gene is localized to human chromosome 14q32.32.

Akt1 active human has been used for the testing of recombinant mouse p21 proteins as its substrates using in vitro protein kinase assay.

AKT1 (v-akt murine thymoma viral oncogene homolog 1) is responsible for the phosphorylation and cytoplasmic localization of CKDN1A (cyclin-dependent kinase (CDK) inhibitor 1, also referred to as p21). However, p21 is one of the CDKNs which normally resides in the nucleus and its cytoplasmic localization, mediated by AKT1, is common to various cancers where it suppresses proteins essential for apoptosis. Studies show that up-regulation of AKT1 serves as a poor prognostic marker in breast cancer, which however, depends upon factors including population, hormone receptor status, and hormonal or trastuzumab therapy status.