ras oncogene

[cage92]

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how ras gtpase mutation is an oncogene ?there is loss of function of gtpase
and how it differes from neurofibromin which is ras gtpase also

 

[aspiringmd1015]

neurofibromin is a ras regulator, you lose it, ras has a giant party, dancing on tables, popping champagne, the whole 9 yards. Ras mutation causes it to be constitutively active, being bound to GTP, continuously sending intracellular signals for the cell to make proteins, and proliferate.

 

[seminoma]

how ras gtpase mutation is an oncogene ?there is loss of function of gtpase
and how it differes from neurofibromin which is ras gtpase also

Ras promotes cell growth. Gain or loss of function has nothing to do with it being a proto-oncogene.

 

[cage92]

thank you guys

 

[cs24]

how ras gtpase mutation is an oncogene ?there is loss of function of gtpase
and how it differes from neurofibromin which is ras gtpase also

ras bound to gtp is active, so if the gtpase activity is gone, ras is constitutively active. ras needs to cleave GTP to GDP to become inactive.

 

[cage92]

but also neurofibromin mutation cause inactivatiom of gtpase so on what basis they classifie ras and neurofibromin as onco and tumor suppee gene

 

[pathologyDO]

but also neurofibromin mutation cause inactivatiom of gtpase so on what basis they classifie ras and neurofibromin as onco and tumor suppee gene

You need to focus on what their normal function is to understand the definition. The Ras protein is a GTPase important in many pathways, and as such it performs a signal cascade function. By mutation it can become oncogenic, meaning that it is constitutively active and promotes tumor growth. On the other hand neurofibromin normally suppresses GTPase function... thus it is inhibiting tumor formation by regulating cellular cascade activity. It suppresses the cell from being a tumor! If you lose its function, there is dysregulation and unlimited cellular signaling and a tumor can then grow as much as it wants.

So bascially proto-oncogene is usually a regular functioning gene that can get overactivated and increases tumor growth, while a tumor-suppressor gene is something that normally provides regulatory functions and will generally be inhibited to allow tumor growth

 

[bdth]

When bound to GTP, Ras is active. The GTPase activity turns Ras off by hydrolyzing the GTP to GDP (Ras is inactive when bound to GDP).

Loss of GTPase activity means that the GTP cannot be hydrolyzed to GDP. Therefore, Ras cannot be turned off and is locked into the active state.