Biochemical characterization of nuclear pore complex protein gp210 oligomers.
The membrane-spanning glycoprotein gp210 is a major component of the nuclear pore complex. This nucleoporin contains a large cisternal N-terminal domain, a short C-terminal cytoplasmic tail, and a single transmembrane segment. We show here that dimers of native gp210 can be isolated from cell extracts by immunoprecipitation, and from purified rat liver nuclear envelopes by velocity sedimentation and gel filtration. Cross-linking of proteins in isolated membranes prior to solubilization dramatically increases the proportion of dimers. The dimers are SDS-resistant, as previously observed for some integral membrane proteins of cis-Golgi and plasma membrane proteins, including glycophorin A. Larger oligomers of gp210 can also be obtained by gel filtration and denaturing electrophoresis, but unlike the dimers are dissociated by reduction and heating in the presence of SDS. We propose that gp210 is organized into the pore membrane as a large array of gp210 dimers that may constitute a luminal submembranous protein skeleton.
Favreau
C
C
Département de Biologie Cellulaire, Institut Jacques Monod, UMR 7592, CNRS/Université Paris 6 & 7, France.
Bastos
R
R
Cartaud
J
J
Courvalin
J C
JC
Mustonen
P
P
D000818:Animals; D003432:Cross-Linking Reagents; D019281:Dimerization; D006367:HeLa Cells; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D022022:Nuclear Pore / Q000737:chemistry*; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D011487:Protein Conformation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology
D003432:Cross-Linking Reagents; D008562:Membrane Glycoproteins; C063865:NUP210 protein, human; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D012967:Sodium Dodecyl Sulfate