Linked Life Data

21454505

Source:http://linkedlifedata.com/resource/pubmed/id/21454505

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
20
pubmed:dateCreated
2011-5-16
pubmed:databankReference
pubmed:abstractText
We have solved the x-ray crystal structures of the RabGAP domains of human TBC1D1 and human TBC1D4 (AS160), at 2.2 and 3.5 Å resolution, respectively. Like the yeast Gyp1p RabGAP domain, whose structure was solved previously in complex with mouse Rab33B, the human TBC1D1 and TBC1D4 domains both have 16 ?-helices and no ?-sheet elements. We expected the yeast Gyp1p RabGAP/mouse Rab33B structure to predict the corresponding interfaces between cognate mammalian RabGAPs and Rabs, but found that residues were poorly conserved. We further tested the relevance of this model by Ala-scanning mutagenesis, but only one of five substitutions within the inferred binding site of the TBC1D1 RabGAP significantly perturbed catalytic efficiency. In addition, substitution of TBC1D1 residues with corresponding residues from Gyp1p did not enhance catalytic efficiency. We hypothesized that biologically relevant RabGAP/Rab partners utilize additional contacts not described in the yeast Gyp1p/mouse Rab33B structure, which we predicted using our two new human TBC1D1 and TBC1D4 structures. Ala substitution of TBC1D1 Met(930), corresponding to a residue outside of the Gyp1p/Rab33B contact, substantially reduced catalytic activity. GLUT4 translocation assays confirmed the biological relevance of our findings. Substitutions with lowest RabGAP activity, including catalytically dead RK and Met(930) and Leu(1019) predicted to perturb Rab binding, confirmed that biological activity requires contacts between cognate RabGAPs and Rabs beyond those in the yeast Gyp1p RabGAP/mouse Rab33B structure.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1083-351X
pubmed:author
pubmed:copyrightInfo
© 2011 by The American Society for Biochemistry and Molecular Biology, Inc.
pubmed:issnType
Electronic
pubmed:day
20
pubmed:volume
286
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
18130-8
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Crystal structures of human TBC1D1 and TBC1D4 (AS160) RabGTPase-activating protein (RabGAP) domains reveal critical elements for GLUT4 translocation.
pubmed:affiliation
Joslin Diabetes Center and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, N.I.H., Extramural