This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Bailey, C F Articles by Bowers, B Search for Related Content PubMed PubMed Citation Articles by Bailey, C F Articles by Bowers, B

 Previous Article  |  Next Article 

Mol Cell Biol. 1981 April; 1(4): 358-369

Localization of lipophosphonoglycan in membranes of Acanthamoeba by using specific antibodies.

Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20205.

ABSTRACT

Antibodies against two electrophoretically distinct forms of lipophosphonoglycan (LPG) were produced in rabbits. Antibody specificity was demonstrated by the coupled antibody 125I-protein A assay (Adair et al., J. Cell Biol. 79:281-285, 1978). Indirect immunofluorescent labeling of intact Acanthamoeba showed that antibodies to both LPG components had the same uniform distribution on the cell surface. Both antibodies also bound to the cytoplasmic surface of isolated phagosomes. The location of LPG in other membranes of the amoeba was demonstrated on sections by the unlabeled antibody method. Although LPG was absent from the nuclear membrane, virtually all of the internal vacuole membranes were labeled, including the contractile vacuole. Antibodies directed against LPG were utilized to label lipophosphonoglycan in the plasma membrane of living amoebae. Labeled membrane was internalized and then localized by immunofluorescence in cytoplasmic vacuoles within 10 min of incubation. Although these results are evidence for exchange between plasma and cytoplasmic vacuolar membranes, the contractile vacuole remained unlabeled and can be considered, therefore, a separate membrane compartment. Concanavalin A also was bound and internalized by the amoeba, but electron microscopy showed that this label caused pronounced membrane perturbation, limiting its usefulness as a membrane marker in this system.