Ras and relatives--job sharing and networking keep an old family together.

摘要: Many members of the Ras superfamily GTPases have been implicated in regulation hematopoietic cells, with roles growth, survival, differentiation, cytokine production, chemotaxis, vesicle-trafficking, and phagocytosis. The well-known p21 proteins H-Ras, N-Ras, K-Ras 4A, 4B are also frequently mutated human cancer leukemia. Besides four proteins, subfamily includes R-Ras, TC21 (R-Ras2), M-Ras (R-Ras3), Rap1A, Rap1B, Rap2A, Rap2B, RalA, RalB. They exhibit remarkable overall amino acid identities, especially regions interacting guanine nucleotide exchange factors that catalyze their activation. In addition, there is considerable sharing various downstream effectors through which they transmit signals GTPase activating downregulate activity, resulting overlap effector function. Relatively little known about physiological functions individual family members, although presence well-conserved orthologs Caenorhabditis elegans suggests both specific vital. structural functional similarities meant commonly used research tools fail to discriminate between different previously attributed one member may be shared other family. Here we discuss differences activation, usage, subfamily. We review possibility differential localization parts cell membrane govern responses activation surface receptors.