Anti-Ras, H (Harvey Murine Sarcoma Virus Oncogene, Ha-Ras)

Ras proteins are small GTP-binding proteins which, unlike the heterotrimeric G-proteins, contain all GTPase and effector functions within a single polypeptide. At least three isoforms of Ras exist, Ki-Ras, Ha-Ras and N-Ras, with distinct expression patterns but similar signaling activity. Ras is palmitoylated and farnesylated at the carboxy terminus, anchoring it in the membrane. In resting cells, Ras is loaded with GDP, and is activated subsequent to growth factor stimulation of receptors, which recruit Ras Guanine nucleotide Exchange Factors to the plane of the membrane. Proximity of exchange factors to the Ras proteins causes release of GDP, and its replacement by GTP. In its GTP-bound form, Ras binds several proteins, including Raf, RalGDS and PI3 Kinase. Inactivation of Ras occurs by GTP hydrolysis, which is greatly accelerated by RasGAP or NF-1, two known Ras GTPase Activating Proteins. It is possible to assay for Ras activation by incubation of lysates with the Ras-binding domain of Raf-1, which selectively binds to Ras:GTP. Applications: Suitable for use in Western Blot. Other applications not tested. Recommended Dilution: Western Blot: 1:1000, Optimal dilutions to be determined by the researcher. Positive Control: A431 cell lysate. Storage and Stability: May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Aliquots are stable for 12 months after receipt. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.