The binding in vitro of modified LDL to the intermediate filament protein vimentin.
Membrane-associated proteins with specific binding properties to modified LDL were investigated in J774 macrophages and Mono Mac 6 sr cells. Ligand blotting of membrane proteins revealed a 54-kDa protein which bound oxidized and acetylated but not native LDL. The 54-kDa protein, isolated by 2D-PAGE, was identified as vimentin. (125)I-AcLDL bound to purified vimentin and desmin in a saturable manner, with an approximate K(d) of 1.7 x 10(-7) M (89 microgram/ml) and 8.0 x 10(-8) M (41 microgram/ml), respectively. Blots of vimentin mutant proteins with deletions in the positively charged N-terminal head domain showed that amino acids 26-39 are essential for the binding of AcLDL by vimentin. Taken together, our data indicate that vimentin binds modified LDL, but not native LDL, in a specific and saturable manner. Vimentin filaments extend throughout the cytoplasm as far as the inner surfaces of plasma and vesicular membranes. Vimentin may thus play a role in membrane-associated steps involved in the intracellular processing of oxidized LDL, contributing to its unregulated uptake and intracellular retention by cells of the atherogenic plaque.
Heidenthal
A K
AK
Institut für Prophylaxe und Epidemiologie der Kreislaufkrankheiten, Universität München, Pettenkoferstrasse 9, Münich, D-80336, Germany.
Weber
P C
PC
Lottspeich
F
F
Hrboticky
N
N
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003893:Desmin / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007457:Iodine Radioisotopes; D007700:Kinetics; D008077:Lipoproteins, LDL / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D009000:Monocytes; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017384:Sequence Deletion; D014746:Vimentin / Q000737:chemistry* / Q000378:metabolism*
D003893:Desmin; D007457:Iodine Radioisotopes; D008077:Lipoproteins, LDL; D008565:Membrane Proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D014746:Vimentin; C032629:acetyl-LDL