Protein kinase B

Protein kinase B (PKB), also known as Akt, is a serine/threonine-specific protein kinase that plays a key role in multiple cellular processes such as glucose metabolism, apoptosis, cell proliferation, transcription and cell migration.

Structure

PKB is a 57 kDa protein that is activated by insulin, growth factors and other signaling molecules. It is composed of three isoforms: PKBα (Akt1), PKBβ (Akt2) and PKBγ (Akt3). Each isoform has a similar structure, but they have different expression patterns and functions.

Function

PKB is involved in the regulation of glucose metabolism by promoting the translocation of the glucose transporter GLUT4 to the cell membrane. It also inhibits apoptosis by phosphorylating and inactivating several targets, including Bad, forkhead transcription factors and caspase-9. In addition, PKB promotes cell proliferation by activating the mTOR pathway and inhibiting the GSK3β pathway.

Role in disease

Abnormal activation of PKB has been implicated in several diseases, including cancer, diabetes, and cardiovascular disease. In cancer, PKB promotes cell survival and growth, and its activation is often associated with resistance to chemotherapy. In diabetes, impaired PKB signaling can lead to insulin resistance and hyperglycemia. In cardiovascular disease, PKB has a protective role by promoting angiogenesis and preventing apoptosis of cardiac cells.

See also

• Protein kinase
• Insulin
• Apoptosis
• Cell proliferation
• Cancer
• Diabetes
• Cardiovascular disease

References

Protein kinase B Resources
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