Ras: Difference between revisions
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== Active and Inactive forms of Ras == | == Active and Inactive forms of Ras == | ||
Ras is in its inactive form when it is bound to [[GDP|GDP]], and becomes active once GDP has been exchanged for a [[GTP|GTP]] molecule. This reaction is initiated by the action of a specific signal molecule binding to a [[RTK receptor|RTK receptor]] on the cell membrane. The activated RTK has intrinsic [[ | Ras is in its inactive form when it is bound to [[GDP|GDP]], and becomes active once GDP has been exchanged for a [[GTP|GTP]] molecule. This reaction is initiated by the action of a specific signal molecule binding to a [[RTK receptor|RTK receptor]] on the cell membrane. The activated RTK has intrinsic [[Kinase|kinase]] activity, and this leads to [[Phosphorylation|phosphorylation]] of docking proteins at the RTK domains. The adaptor protein [[Grb-2|Grb-2]] mediates the reaction between the RTK and Ras [[GEF|GEF]], which exchanges GDP for GTP, acvtivating Ras which can transmit of a signal along multiple pathways. The inactivation of Ras is controlled by GTP [[Hydrolysis|hydrolysis]] <ref>Alberts, B, et al, 2008. Molecular Biology of the Cell. 5th ed. United States of America: Garland Science.</ref>.<br> | ||
=== References: === | === References: === | ||
<references /> | <references /> | ||
Revision as of 22:17, 24 October 2012
The Ras protein is a monomeric G-protein with weak GTPase enzyme activity. It is a signal-transducer protein for growth factors and therefore it helps to transfer signals from cell-surface Receptor Tyrosine Kinase (RTK) receptors to the nucleus [1].
Active and Inactive forms of Ras
Ras is in its inactive form when it is bound to GDP, and becomes active once GDP has been exchanged for a GTP molecule. This reaction is initiated by the action of a specific signal molecule binding to a RTK receptor on the cell membrane. The activated RTK has intrinsic kinase activity, and this leads to phosphorylation of docking proteins at the RTK domains. The adaptor protein Grb-2 mediates the reaction between the RTK and Ras GEF, which exchanges GDP for GTP, acvtivating Ras which can transmit of a signal along multiple pathways. The inactivation of Ras is controlled by GTP hydrolysis [2].