Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2000-3-8
pubmed:abstractText
The MIP (major intrinsic protein) family is a widespread family of membrane proteins exhibiting two major types of channel properties: aquaporins and solute facilitators. In the present study, freeze-fracture electron microscopy was used to investigate the oligomerization state of two MIP proteins heterologously expressed in the plasma membrane of Xenopus laevis oocytes: AQPcic, an aquaporin from the insect Cicadella viridis, and GlpF, a glycerol facilitator from Escherichia coli. Swelling assays performed on oocytes 48 and 72 h following cRNA microinjections showed that these proteins were functionally expressed. Particle density determinations indicated that expression of proteins is related to an increase in particle density on the P fracture face of oocyte plasma membranes. Statistical analysis of particle sizes was performed on protoplasmic fracture faces of the plasma membrane of oocytes expressing AQPcic and GlpF 72 h after cRNA microinjections. Compared to control oocytes, AQPcic-expressing oocytes exhibited a specific population of particles with a mean diameter of 8.7 +/- 0.1 nm. This value is consistent with the previously reported tetrameric organization of AQPcic. In addition, AQPcic particles aggregate and form orthogonal arrays similar to those observed in native membranes of C. viridis, consisting of homotetramers of AQPcic. On the protoplasmic fracture face of oocytes expressing GlpF, the particle density is increased by 4.1-fold and the mean diameter of specifically added particles is 5.8 +/- 0.1 nm. This value fits with a monomer of the 28-kDa GlpF protein plus the platinum-carbon layer. These results clearly demonstrate that GlpF is a monomer when functionally expressed in plasma membranes of Xenopus oocytes and therefore emphasize the key role of the oligomerization state of MIP proteins with respect to their function.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/AQPcic protein, Cicadella viridis, http://linkedlifedata.com/resource/pubmed/chemical/Aquaporins, http://linkedlifedata.com/resource/pubmed/chemical/Bacterial Outer Membrane Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Bacterial Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Escherichia coli Proteins, http://linkedlifedata.com/resource/pubmed/chemical/FkpA protein, E coli, http://linkedlifedata.com/resource/pubmed/chemical/GlpF protein, E coli, http://linkedlifedata.com/resource/pubmed/chemical/Immunophilins, http://linkedlifedata.com/resource/pubmed/chemical/Insect Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Membrane Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Peptidylprolyl Isomerase
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1047-8477
pubmed:author
pubmed:copyrightInfo
Copyright 1999 Academic Press.
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
128
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
287-96
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:10633068-Animals, pubmed-meshheading:10633068-Aquaporins, pubmed-meshheading:10633068-Bacterial Outer Membrane Proteins, pubmed-meshheading:10633068-Bacterial Proteins, pubmed-meshheading:10633068-Cell Membrane Permeability, pubmed-meshheading:10633068-Cloning, Molecular, pubmed-meshheading:10633068-Escherichia coli, pubmed-meshheading:10633068-Escherichia coli Proteins, pubmed-meshheading:10633068-Freeze Fracturing, pubmed-meshheading:10633068-Gene Expression, pubmed-meshheading:10633068-Immunophilins, pubmed-meshheading:10633068-Insect Proteins, pubmed-meshheading:10633068-Membrane Proteins, pubmed-meshheading:10633068-Microscopy, Electron, pubmed-meshheading:10633068-Oocytes, pubmed-meshheading:10633068-Particle Size, pubmed-meshheading:10633068-Peptidylprolyl Isomerase, pubmed-meshheading:10633068-Protein Structure, Quaternary, pubmed-meshheading:10633068-Xenopus
pubmed:year
1999
pubmed:articleTitle
Oligomerization state of MIP proteins expressed in Xenopus oocytes as revealed by freeze-fracture electron-microscopy analysis.
pubmed:affiliation
Equipe Canaux et Récepteurs Membranaires, UPRES-A CNRS 6026, Rennes Cedex, Bretagne, 35042, France. Patrik.Bron@univ-rennes1.fr
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't