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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2002-10-16
pubmed:abstractText
Dynamin is a GTPase protein that is essential for clathrin-mediated endocytosis of synaptic vesicle membranes. The Drosophila dynamin mutation shi(ts1) changes a single residue (G273D) at the boundary of the GTPase domain. In cell fractionation of homogenized fly heads without monovalent cations, all dynamin was in pellet fractions and was minimally susceptible to Triton-X extraction. Addition of Na(+) or K(+) can extract dynamin to the cytosolic (supernatant) fraction. The shi(ts1) mutation reduced the sensitivity of dynamin to salt extraction compared with other temperature-sensitive alleles or wild type. Sensitivity to salt extraction in shi(ts1) was enhanced by GTP and nonhydrolyzable GTP-gammaS. The shi(ts1) mutation may therefore induce a conformational change, involving the GTP binding site, that affects dynamin aggregation. Temperature-sensitive shibire mutations are known to arrest endocytosis at restrictive temperatures, with concomitant accumulation of presynaptic collared pits. Consistent with an effect upon dynamin aggregation, intact shi(ts1) flies recovered much more slowly from heat-induced paralysis than did other temperature-sensitive shibire mutants. Moreover, a genetic mutation that lowers GTP abundance (awd(msf15)), which reduces the paralytic temperature threshold of other temperature-sensitive shibire mutations that lie closer to consensus GTPase motifs, did not reduce the paralytic threshold of shi(ts1). Taken together, the results may link the GTPase domain to conformational shifts that influence aggregation in vitro and endocytosis in vivo, and provide an unexpected point of entry to link the biophysical properties of dynamin to physiological processes at synapses.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0022-3034
pubmed:author
pubmed:copyrightInfo
Copyright 2002 Wiley Periodicals, Inc.
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
53
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
319-29
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Unique biochemical and behavioral alterations in Drosophila shibire(ts1) mutants imply a conformational state affecting dynamin subcellular distribution and synaptic vesicle cycling.
pubmed:affiliation
Department of Biological Sciences, University of Iowa, Iowa City, IA 52242, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't