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Protein interaction causes brain tumors
Issue date: 3/13/08
Researchers from the Sidney Kimmel Comprehensive Cancer Center at the Hopkins medical school have uncovered a detailed interaction between two proteins involved in medulloblastoma, a common type of brain cancer.
This group of researchers has characterized and shown that two proteins involved in the repression of tumor formation work together to switch-off a third protein, which can lead to medulloblastoma formation.
Medulloblastoma is the most common nervous system cancer in children and is thought to arise from granule cell precursors (GCPs) in the cerebellum. The cerebellum, which means "little brain," aids in the integration between sensory inputs and motor control outputs.
It is mainly composed of granule cells, which are tiny in comparison to other neurons of the brain. This characteristic of the granule cells allows the cerebellum take up only 10 percent of the brain's size, but roughly 50 percent of the brain's neurons.
The Hedgehog pathway is involved in many developmental processes, in the cerebellum as well as in other parts of the body. During development, cells in the brain secrete Sonic Hedgehog, a protein that activates the Hedgehog pathway.
This pathway is used extensively in the formation of granule cells from granule precursor cells.
PATCHED-1 (Ptch1) is a receptor on the cell-surface of GCPs that binds to the Sonic Hedgehog protein, thereby activating the Hedgehog pathway within a cell. However, when not activated by this ligand, Ptch1 is also a tumor suppressor protein.
In its presence, it stops the formation of tumors, and in its absence, tumors can form. Interestingly, fewer than 25 percent of medulloblastoma cancers have mutations in the Hedgehog pathway.
The researchers from the medical school wanted to determine what other proteins are involved in the formation of medulloblastoma. Previous work done in the field has shown that mutations, or alterations, to the genome at a certain point show a higher incidence of medulloblastoma formation.
This group of researchers has characterized and shown that two proteins involved in the repression of tumor formation work together to switch-off a third protein, which can lead to medulloblastoma formation.
Medulloblastoma is the most common nervous system cancer in children and is thought to arise from granule cell precursors (GCPs) in the cerebellum. The cerebellum, which means "little brain," aids in the integration between sensory inputs and motor control outputs.
It is mainly composed of granule cells, which are tiny in comparison to other neurons of the brain. This characteristic of the granule cells allows the cerebellum take up only 10 percent of the brain's size, but roughly 50 percent of the brain's neurons.
The Hedgehog pathway is involved in many developmental processes, in the cerebellum as well as in other parts of the body. During development, cells in the brain secrete Sonic Hedgehog, a protein that activates the Hedgehog pathway.
This pathway is used extensively in the formation of granule cells from granule precursor cells.
PATCHED-1 (Ptch1) is a receptor on the cell-surface of GCPs that binds to the Sonic Hedgehog protein, thereby activating the Hedgehog pathway within a cell. However, when not activated by this ligand, Ptch1 is also a tumor suppressor protein.
In its presence, it stops the formation of tumors, and in its absence, tumors can form. Interestingly, fewer than 25 percent of medulloblastoma cancers have mutations in the Hedgehog pathway.
The researchers from the medical school wanted to determine what other proteins are involved in the formation of medulloblastoma. Previous work done in the field has shown that mutations, or alterations, to the genome at a certain point show a higher incidence of medulloblastoma formation.
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