Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Netrin-1 and its receptors DCC (deleted in colorectal cancer) and the UNC5 orthologues (human UNC5A-D and rodent UNC5H1-4) define a new mechanism for both the positive (induction) and negative (suppression) regulation of apoptosis. Accumulating evidence implies that for human cancers, this positive signalling pathway is frequently inactivated. Surprisingly, binding of netrin-1 to its receptors inhibits tumour suppressor p53-dependent apoptosis, and p53 is directly involved in transcriptional regulation of netrin-1 and its receptors. So, the netrin-1 receptor pathways probably play an important part in tumorigenesis.
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PMID:Netrin-1 and its receptors in tumorigenesis. 1557 19

Growth cone response to the bifunctional guidance cue netrin-1 is regulated by the activity of intracellular signaling intermediates such as protein kinase C-alpha (PKCalpha) and adenylyl cyclase. Among the diverse cellular events these enzymes regulate is receptor trafficking. Netrin-1, itself, may govern the activity of these signaling intermediates, thereby regulating axonal responses to itself. Alternatively, other ligands, such as activators of G protein-coupled receptors, may regulate responses to netrin-1 by governing these signaling intermediates. Here, we investigate the mechanisms controlling activation of PKCalpha and the subsequent downstream regulation of cell surface UNC5A receptors. We report that activation of adenosine receptors by adenosine analogs, or activation of the putative netrin-1 receptor, the G protein-coupled receptor adenosine A2b receptor (A2bR) results in PKCalpha-dependent removal of UNC5A from the cell surface. This decrease in cell surface UNC5A reduces the number of growth cones that collapse in response to netrin-1 and converts repulsion to attraction. We show these A2bR-mediated alterations in axonal response are not because of netrin-1 because netrin-1 neither binds A2bR, as assayed by protein overlay, nor stimulates PKCalpha-dependent UNC5A surface loss. Our results demonstrate that netrin-1-independent A2bR signaling governs the responsiveness of a neuron to netrin-1 by regulating the levels of cell surface UNC5A receptor.
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PMID:Netrin-1-independent adenosine A2b receptor activation regulates the response of axons to netrin-1 by controlling cell surface levels of UNC5A receptors. 1799 30

UNC5A is an axon-guidance molecule, and plays a critical role in neuronal development and differentiation as a netrin-1 receptor. Emerging evidence suggests that axon guidance molecules including UNC5A regulate apoptosis in non-neuronal cells. Here, we report that UNC5A regulates apoptosis as a downstream target of p53. UNC5A expression was strongly induced by exogenous and endogenous p53. Chromatin immunoprecipitation (ChIP) revealed that p53 binds to a sequence in the promoter region of the UNC5A gene. Reporter assays showed that this sequence exhibits p53-dependent transcriptional activity. Overexpression of UNC5A significantly suppressed colony formation of two glioblastoma cell lines-U373MG and T98G. UNC5A dramatically induced apoptosis through the activation of caspase-3 in various cancer cell lines, including LS174T (colon cancer), U373MG (glioblastoma), SH-SY5Y (neuroblastoma), and SKNAS (neuroblastoma). Finally, gamma irradiation strongly induced the expression of UNC5A mRNA in the spleen and colon of p53+/+ mice, but not in those of p53-/- mice, implying that the transcription of UNC5A in vivo is regulated by p53. These results suggest that UNC5A is a novel transcriptional target of p53 and plays a role in p53-dependent apoptosis.
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PMID:Identification of UNC5A as a novel transcriptional target of tumor suppressor p53 and a regulator of apoptosis. 2037