Sari GTPase

Jones B, Jones EL, Bonney SA, Patel HN, Mensenkamp AR, Eichenbaum-Voline S, Rudling M, Myrdal U, Annesi G, Naik S, Meadows N, Quattrone A, Islam SA, Naoumova RP, Angelin B, Infante R, Levy E, Roy CC, Freemont PS, Scott J, Shoulders CC (2003) Mutations in a Sari GTPase of COPII vesicles are associated with lipid absorption disorders. Nat Genet 34 29-31... 

Weissman, J. T., Plutner, H., and Balch, W. E. (2001). The mammalian guanine nucleotide exchange factor mSecl2 is essential for activation of the Sari GTPase directing endoplasmic reticulum export. Traffic 2, 465-475. 

Drawing on the structural similarities of Sari and ARF to other small GTPase switch proteins, researchers have... 

Small GTP-binding proteins (ARF or Sari) belonging to the GTPase superfamily control polymerization of coat proteins, the initial step in vesicle budding (see Figure 17-9). After vesicles are released from the donor membrane, hydrolysis of GTP bound to ARF or Sari triggers disassembly of the vesicle coats. 

COPII association with ER membranes (Stroud et al, 2003). Furthermore, it should be noted that in the case of Sari the GTP-restricted protein has been the microinjected protein of choice not because it is the right mutant protein but because it is easier to isolate than the GDP-restricted mutant in stable, high activity form. As a final buyer beware note, the reader is reminded that small GTPase are in general lipid modified and that these modifications typically are not produced when isolating the recombinant, his-tagged protein from E. coli. The experimenter hopes that the injected cell will do what E. coli did not. 

The Sec23 subunit of the Sec23/24 complex is the GAP for the GTPase, Sari (Aridor et al, 2001 Kuge et al, 1994). This property can be used to assess the function of the Sec23/24 complex in an in vitro GTPase assay. 

The conversion of GTP labeled with at the alpha position to GDP can be monitored using thin layer chromatography (TLC) (Aridor et al., 1998). Sari has very low intrinsic GTPase activity, which is activated through its interaction with Sec23, providing an indication of the functionality of the... 

We routinely measure PLD activity using ethanol as a substrate. A 2-stage assay is recommended to measure the effects of small GTPases on PLD activity. In first stage of the assay, recombinant GTPases (Sari or... 

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