What is a PTEN signaling pathway?

The PTEN network encompasses signals from growth factor receptors on the cell surface to transcription factors that act in the nucleus, complete with interconnections to other tumor suppressor and oncogenic signaling pathways. A simple schematic view of the PTEN pathway is shown in Figure 1.

How is PTEN activated?

PTEN works in direct opposition to PI3K, dephosphorylating PIP3 to PIP2. AKT binds to PIP3 and is activated by phosphorylation on threonine (T)308 by PDK1 and serine (S)473 by mTORC2. AKT phosphorylates and inactivates many downstream targets, resulting in increased cellular survival and proliferation.

What is the function of PTEN?

The PTEN gene provides instructions for making an enzyme that is found in almost all tissues in the body. The enzyme acts as a tumor suppressor, which means that it helps regulate cell division by keeping cells from growing and dividing (proliferating) too rapidly or in an uncontrolled way.

Is PTEN a tumor suppressor or oncogene?

PTEN is a well-known tumor suppressor protein that regulates a number of cellular processes, including cell death and proliferation, through the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway (2,3).

Why is PTEN an important tumor suppressor?

In addition, PTEN is linked via several mechanisms to the p53 tumor suppressor. Through p53 and additional mechanisms, loss of PTEN leads to genomic instability. Hence, PTEN is important because its loss misregulates multiple Akt-dependent and -independent pathways critical for the development of cancer.

What does PTEN do insulin?

Phosphatase and tensin homolog (PTEN) functions as a lipid phosphatase dephosphorylating the lipid phosphatidylinositol (3,4,5)-trisphosphate (PIP3) to phosphatidylinositol (4,5)-bisphosphate (PIP2) and inhibits the insulin signaling pathway by antagonizing phosphatidylinositol 3′-kinase (PI3K) function.

Why is PTEN a tumor suppressor?

Why PTEN is classified as a Tumour suppressor?

PTEN acts as a tumor suppressor gene through the action of its phosphatase protein product. This phosphatase is involved in the regulation of the cell cycle, preventing cells from growing and dividing too rapidly.

How does PTEN suppress tumor growth?

A series of publications over the past year now suggest a mechanism by which PTEN loss of function results in tumors. PTEN appears to negatively control the phosphoinositide 3-kinase signaling pathway for regulation of cell growth and survival by dephosphorylating the 3 position of phosphoinositides.

Is PTEN a protein or enzyme?

PTEN is a 403-amino acid protein that shares sequence homology with tensin and auxilin at its amino-terminal.

What regulates PTEN?

PTEN is under extensive regulation by miRNAs. Specific miRNAs target mRNAs by binding to miRNA response elements usually located at the 3′ untranslated region (UTR) of target mRNAs121. A number of miRNAs have been found to participate in the regulation of metabolic disease and cancer by targeting PTEN122,123 (Fig.