Endogenous sphingomyelin segregates into submicrometric domains in the living erythrocyte membrane.

ABSTRACT: We recently reported that trace insertion of exogenous fluorescent (green BODIPY) analogs of sphingomyelin (SM) into living red blood cells (RBCs), partially spread onto coverslips, labels submicrometric domains, visible by confocal microscopy. We here extend this feature to endogenous SM, upon binding of a SM-specific nontoxic (NT) fragment of the earthworm toxin, lysenin, fused to the red monomeric fluorescent protein, mCherry [construct named His-mCherry-NT-lysenin (lysenin*)]. Specificity of lysenin* binding was verified with composition-defined liposomes and by loss of (125)I-lysenin* binding to erythrocytes upon SM depletion by SMase. The (125)I-lysenin* binding isotherm indicated saturation at 3.5 × 10(6) molecules/RBC, i.e., ∼3% of SM coverage. Nonsaturating lysenin* concentration

SUBMITTER: Carquin M 

PROVIDER: S-EPMC4076090 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature