J. Biol. Chem., Vol. 261, Issue 23, 10558-10568, 08, 1986
Interaction in vitro of nonepithelial intermediate filament proteins with total cellular lipids, individual phospholipids, and a phospholipid mixture
P Traub, G Perides, H Schimmel and A Scherbarth
The interaction of nonepithelial intermediate filament (IF) proteins with
vesicles produced from total Ehrlich ascites tumor cell lipids results in
the formation of complexes which in sucrose density gradient centrifugation
attain positions distinctly different from those of the original reactants.
In KBr density gradient equilibrium centrifugation, the IF protein-lipid
adducts accumulate as thin proteolipid films on top of the KBr gradients,
whereas in the absence of lipids the proteins remain distributed within the
density gradients. Similar results were obtained with vesicles derived from
individual phospholipids and a mixture thereof. The affinity of IF proteins
for negatively charged phospholipids is greater than that for vesicles
derived from uncharged phospholipids. Limited digestion of IF proteins with
various proteinases demonstrated that for optimal association of the
reactants IF proteins must carry an intact N terminus and that the isolated
N- terminal polypeptide itself shows strong reactivity with lipid vesicles.
Arginine-phosphate interactions between the N terminus and phospholipids
seem to be partly responsible for this association. However, as shown by
hydrophobic interaction chromatography on phenyl- and octyl-Sepharose 4B,
IF proteins and their proteolytic derivatives also appear to have high
affinities for aromatic and aliphatic substructures of biologically
important molecules. The results are discussed in terms of a possible
functional role of IF protein-lipid interactions in the association of
nonepithelial intermediate filaments with intracellular membrane systems.
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