Ras GTPase

Ras, from "Rat sarcoma virus", is a <a href="/facts/Protein_family/EHt5xwCA">family of related proteins</a> that are expressed in all animal cell lineages and organs. All Ras protein family members belong to a class of protein called <a href="/facts/Small_GTPase/GnBmVEMP">small GTPase</a>, and are involved in transmitting signals within cells (<a href="/facts/Cell_(biology)/bLM9UQvy">cellular</a> <a href="/facts/Signal_transduction/1bs0Me6w">signal transduction</a>). Ras is the prototypical member of the <a href="/facts/Ras_superfamily/2DsdANGx">Ras superfamily</a> of proteins, which are all related in three-dimensional structure and regulate diverse cell behaviours.
When Ras is 'switched on' by incoming signals, it subsequently switches on other proteins, which ultimately turn on genes involved in <a href="/facts/Cell_growth/wbArMaJU">cell growth</a>, <a href="/facts/Differentiation_(cellular)/bCVqUG7w">differentiation</a>, and <a href="/facts/Apoptosis/8dVzSm4y">survival</a>. Mutations in Ras genes can lead to the production of permanently activated Ras proteins, which can cause unintended and overactive signaling inside the cell, even in the absence of incoming signals.
Because these signals result in cell growth and division, overactive Ras signaling can ultimately lead to <a href="/facts/Cancer/PVW6n1D0">cancer</a>. The three Ras genes in humans (<a href="/facts/HRAS/tc0839fm">HRAS</a>, <a href="/facts/KRAS/NSVQ0ALz">KRAS</a>, and <a href="/facts/Neuroblastoma_RAS_viral_oncogene_homolog/qFhmvKBr">NRAS</a>) are the most common <a href="/facts/Oncogene/WLFu6Ma5">oncogenes</a> in human cancer; mutations that permanently activate Ras are found in 20 to 25% of all human tumors and up to 90% in certain types of cancer (e.g., <a href="/facts/Pancreatic_cancer/6h9GIInW">pancreatic cancer</a>). For this reason, Ras inhibitors are being studied as a treatment for cancer and other diseases with Ras overexpression.

Ras GTPase open-in-new

Ras GTPase