The mammalian Rab family of small GTPases: definition of family and subfamily sequence motifs suggests a mechanism for functional specificity in the Ras superfamily 1 1Edited by M. Yaniv

2000 ◽  
Vol 301 (4) ◽  
pp. 1077-1087 ◽  
Author(s):  
José B Pereira-Leal ◽  
Miguel C Seabra
Keyword(s):  
Small Gtpases ◽  
Sequence Motifs ◽  
Functional Specificity ◽  
Ras Superfamily ◽  
Rab Family ◽  
Definition Of

scholarly journals p190 RhoGAP, the major RasGAP-associated protein, binds GTP directly.

1994 ◽  
Vol 14 (11) ◽  
pp. 7173-7181 ◽  
Author(s):  
R Foster ◽  
K Q Hu ◽  
D A Shaywitz ◽  
J Settleman
Keyword(s):  
Structural Features ◽  
Cellular Protein ◽  
Small Gtpases ◽  
Sequence Motifs ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Gtp Binding ◽  
Guanine Nucleotide Binding ◽  
Complex Forms ◽  
Carboxy Terminal

In mitogenically stimulated cells, a specific complex forms between the Ras GTPase-activating protein (RasGAP) and the cellular protein p190. We have previously reported that p190 contains a carboxy-terminal domain that functions as a GAP for the Rho family GTPases. Thus, the RasGAP-p190 complex may serve to couple Ras- and Rho-mediated signalling pathways. In addition to its RhoGAP domain, p190 contains an amino-terminal domain that contains sequence motifs found in all known GTPases. Here, we report that p190 binds GTP and GDP through this conserved domain and that the structural requirements for binding are similar to those seen with other GTPases. While the purified protein is unable to hydrolyze GTP, we detect an activity in cell lysates that can promote GTP hydrolysis by p190. A mutated form of p190 that fails to bind nucleotide retains its RasGAP binding and RhoGAP activities, indicating that GTP binding by p190 is not required for these functions. The sequence of p190 in the GTP-binding domain, which shares structural features with both the Ras-like small GTPases and the larger G proteins, suggests that this protein defines a novel class of guanine nucleotide-binding proteins.

scholarly journals Two New Ypt GTPases Are Required for Exit From the Yeast trans-Golgi Compartment

1997 ◽  
Vol 137 (3) ◽  
pp. 563-580 ◽  
Author(s):  
Gregory Jedd ◽  
Jon Mulholland ◽  
Nava Segev
Keyword(s):  
Protein Transport ◽  
Small Gtpases ◽  
Yeast Cells ◽  
Secretory Vesicles ◽  
Golgi Compartment ◽  
Rab Family ◽  
Vacuolar Protein ◽  
Exocytic Pathway ◽  
Mutant Cells

Small GTPases of the Ypt/rab family are involved in the regulation of vesicular transport. These GTPases apparently function during the targeting of vesicles to the acceptor compartment. Two members of the Ypt/rab family, Ypt1p and Sec4p, have been shown to regulate early and late steps of the yeast exocytic pathway, respectively. Here we tested the role of two newly identified GTPases, Ypt31p and Ypt32p. These two proteins share 81% identity and 90% similarity, and belong to the same protein subfamily as Ypt1p and Sec4p. Yeast cells can tolerate deletion of either the YPT31 or the YPT32 gene, but not both. These observations suggest that Ypt31p and Ypt32p perform identical or overlapping functions. Cells deleted for the YPT31 gene and carrying a conditional ypt32 mutation exhibit protein transport defects in the late exocytic pathway, but not in vacuolar protein sorting. The ypt31/ 32 mutant secretory defect is clearly downstream from that displayed by a ypt1 mutant and is similar to that of sec4 mutant cells. However, electron microscopy revealed that while sec4 mutant cells accumulate secretory vesicles, ypt31/32 mutant cells accumulate aberrant Golgi structures. The ypt31/32 phenotype is epistatic to that of a sec1 mutant, which accumulates secretory vesicles. Together, these results indicate that the Ypt31/32p GTPases are required for a step that occurs in the transGolgi compartment, between the reactions regulated by Ypt1p and Sec4p. This step might involve budding of vesicles from the trans-Golgi. Alternatively, Ypt31/ 32p might promote secretion indirectly, by allowing fusion of recycling vesicles with the trans-Golgi compartment.

The Ras Superfamily of Small GTPases: The Unlocked Secrets

2013 ◽  
pp. 1-18 ◽  
Author(s):  
Luca Goitre ◽  
Eliana Trapani ◽  
Lorenza Trabalzini ◽  
Saverio Francesco Retta
Keyword(s):  
Small Gtpases ◽  
Ras Superfamily

scholarly journals Rab GTPases in Osteoclastic Endomembrane Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Michèle Roy ◽  
Sophie Roux
Keyword(s):  
Plasma Membrane ◽  
Small Gtpases ◽  
Vesicular Trafficking ◽  
Degradation Pathways ◽  
Rab Gtpases ◽  
Bone Homeostasis ◽  
Rab Family ◽  
Autophagic Degradation

Osteoclasts (OCs) are bone-resorbing cells that maintain bone homeostasis. OC differentiation, survival, and activity are regulated by numerous small GTPases, including those of the Rab family, which are involved in plasma membrane delivery and lysosomal and autophagic degradation pathways. In resorbing OCs, polarized vesicular trafficking pathways also result in formation of the ruffled membrane, the resorbing organelle, and in transcytosis.

scholarly journals Small GTPases of the Ras superfamily regulate intestinal epithelial homeostasis and barrier function via common and unique mechanisms

2013 ◽  
Vol 1 (5) ◽  
pp. e26938 ◽  
Author(s):  
Alí Francisco Citalán-Madrid ◽  
Alexander García-Ponce ◽  
Hilda Vargas-Robles ◽  
Abigail Betanzos ◽  
Michael Schnoor
Keyword(s):  
Barrier Function ◽  
Small Gtpases ◽  
Intestinal Epithelial ◽  
Epithelial Homeostasis ◽  
Ras Superfamily

scholarly journals Crystal structure of the FYCO1 RUN domain suggests possible interfaces with small GTPases

2020 ◽  
Vol 76 (8) ◽  
pp. 326-333
Author(s):  
Shunya Sakurai ◽  
Toshiyuki Shimizu ◽  
Umeharu Ohto
Keyword(s):  
Crystal Structure ◽  
Adaptor Protein ◽  
Docking Studies ◽  
Small Gtpases ◽  
Interaction Partner ◽  
Directed Transport ◽  
Ras Superfamily ◽  
Interaction Interface ◽  
Specific Effector

FYCO1 is a multidomain adaptor protein that plays an important role in autophagy by mediating the kinesin-dependent microtubule plus-end-directed transport of autophagosomes. FYCO1 contains a RUN domain, which is hypothesized to function as a specific effector for members of the Ras superfamily of small GTPases, but its role has not been well characterized and its interaction partner(s) have not been identified. Here, the crystal structure of the FYCO1 RUN domain was determined at 1.3 Å resolution. The overall structure of the FYCO1 RUN domain was similar to those of previously reported RUN domains. Detailed structural comparisons with other RUN domains and docking studies suggested a possible interaction interface of the FYCO1 RUN domain with small GTPases of the Ras superfamily.

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