Phosphatase and tensin homolog PTEN

Inactivation of these signaling pathways is mediated by phosphoinositide-specilic phosphatases such as phosphatase and tensin homolog (PTEN). PTEN is a tumor suppressor protein that is mutated in several human cancers. Loss of PTEN results in unregulated cell survival, and thus aberrant cell growth. 

The loss of function deletion/mutation in the phosphatase and tensin homolog (PTEN) tumor-suppressor loeus is found to occur in 30 0% of GBM patients [16, 17]. PTEN is a regulator of the pro-growth kinases, PI3K and AKT. Phosphorylation of these proteins can activate pro-growth/pro-survival... 

All phosphoinositides are found in the cytosolic half of the lipid bilayer of the plasma or intracellular compartment membranes (left part). The different kinases acting on phosphoinositides in mammalian cells are shown in solid lines and the phosphoinositide 3-kinases, in bold. The phosphoinositides counterpart pathways catalysed by known phosphatases are represented by dashed lines. The best known phosphatases are PTEN (Phosphatase and tensin homolog deleted on chromosome 10) and SHIP (SH2 domain-containing inositol 5-phosphatase). 

Phospholipid phosphatases are enzymes such as SHIP (SH2-domain containing inositide-5-phosphatase) or PTEN (phosphatase and tensin homolog deleted on chromosome 10) which dephosphorylate phosphoino-sitides. Whereas SHIP removes phosphate from the 5 ... 

PBD peroxisome biogenesis disorders PTEN phosphatase and tensin homolog... 

PTEN, phosphatase and tensin homolog PTPase, phosphotyrosine phosphatase PYY, peptide YY... 

Qiao, J., Kang, J., Cree, J., Evers, B. M., Chung, D. H. (2005). Gastrin-releasing peptide-induced down-regulation of tumor suppressor protein PTEN (phosphatase and tensin homolog deleted on chromosome ten) in neuroblastomas. Annals of Surgery, 241, 684-691. 

LAST2 - large tumor suppressor 2 PTEN - phosphatase and tensin homolog TPMl - tumor-suppressor tropomyosin-1. 

Table VIII Phosphatase and Tensin Homolog on Chromosome Ten (PTEN)...

Figure 3. Pathways of phosphoinositide synthesis and interconversions. The figure shows the main pathways of phosphoinositide synthesis in mammalian cells. For the sake of clarity only the enzymatic activities (3-, 4- or 5-kinases or phosphatases) are indicated. In some cases the identification of key enzymes is mentioned (class I, II and III PI 3-kinases, PTEN, MTM, MTMR or SHIP). PI3K, phosphoinositide 3-kinase. PTEN, phosphatase and tensin homolog deleted on chromosome ten. MTM, myotubularin. MTMR, myotubular myopathy-related protein. SHIP, Src homology 2-containing inositol 5-phosphatase. PLC, phospholipase C. DAG, diacylglycerol.

Figure 50. PTEN. The tumor suppressor gene and gene product protein PTEN (phosphatase tensin homolog deleted on chromosome ten, human 10q23.3) (Table VIII), is the natural inhibitor of oncogenes PI3K/Akt (phosphatidyl inositol kinase 3 protein kinase 3 phosphatidylinositol 3 phosphate Jacob Furth s AK mouse strain thymic lymphoma retroviral oncogene phosphoinosite-dependent kinase). The PTEN protein inactivates PIP3 by dephosphorylation PDKl (phosphoinositol-dependent kinase) is not recruited to the plasma membrane to activate Akt by phosphorylation. Sarah M. Planchon et al. The nuclear affairs of PTEN. J Cell Sci 2008 121 249-253. doi 10.1242/jcs.022459...

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