Antibody-specific detection of caveolin-1 in subapical compartments of MDCK cells
William S Bush1, Gudrun Ihrke, John M Robinson
1Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 718 Light Hall, Nashville, TN 37232, USA.
Insights
Caveolin-1
Area of Science:
- Cell Biology
- Molecular Biology
- Protein Localization
Background:
- Caveolin-1 is a primary structural protein of caveolae and is also present in the Golgi complex.
- Caveolin-1's presence in other cellular compartments like recycling endosomes is infrequently observed.
- The reasons for the intermittent detection of caveolin-1 in various cellular locations remain unclear.
Purpose of the Study:
- To investigate if non-caveolar, non-Golgi caveolin-1 exhibits unique or fixation-dependent epitopes.
- To compare the efficacy of different caveolin-1 antibodies in detecting distinct subcellular pools.
- To clarify the full subcellular distribution of caveolin-1.
Main Methods:
- Immunofluorescence microscopy was employed in Madin-Darby canine kidney (MDCK) cells.
- A panel of antibodies targeting different domains of caveolin-1 was used.
- Antibody binding and epitope accessibility under varying fixation conditions were assessed.
Main Results:
- Three N-terminal targeting antibodies identified a novel caveolin-1 pool in the subapical region of MDCK cells, associated with endosomal recycling compartments.
- Antibody-dependent variations in cell surface caveolin-1 labeling were observed.
- The detection of caveolin-1 epitopes was significantly influenced by fixation methods.
Conclusions:
- The subcellular distribution of caveolin-1 is potentially more widespread than previously recognized.
- No single antibody or fixation protocol can simultaneously detect all cellular caveolin-1.
- Understanding epitope accessibility is crucial for accurately mapping caveolin-1 localization.
Abstract:
Caveolin-1 is the major structural component of caveolae and is also found in the Golgi complex of many cell types. Occasionally, caveolin-1 has been observed in additional intracellular compartments, including recycling endosomes. Why caveolin-1 expression is detected at these sites only infrequently is not clear. In this study, we test the hypothesis that non-caveolar, non-Golgi pools of caveolin-1 display unique and/or fixation-dependent epitopes. We compared the ability of a panel of antibodies raised against various domains of caveolin-1 to detect distinct subcellular pools of the protein by immunofluorescence microscopy in Madin-Darby canine kidney (MDCK) cells, a cell line where the subcellular localization of caveolin-1 has been extensively characterized. We show that three antibodies directed to the N-terminus of caveolin-1 recognize a previously undetected pool of caveolin-1 in the subapical region of MDCK cells, a localization characteristic of endosomal recycling compartments. The antibodies vary in their ability to label caveolin-1 at the cell surface, and the epitopes detected by each are highly fixation dependent. Our findings suggest that no single caveolin antibody or staining condition is capable of detecting all the caveolin-1 in a cell simultaneously. Consequently, the subcellular distribution of caveolin-1 may be much broader than currently believed.
More Related Videos
10:50Isolation of Labile Multi-protein Complexes by in vivo Controlled Cellular Cross-Linking and Immuno-magnetic Affinity Chromatography
Published on: March 9, 2010
12:15The C. elegans Intestine As a Model for Intercellular Lumen Morphogenesis and In Vivo Polarized Membrane Biogenesis at the Single-cell Level: Labeling by Antibody Staining, RNAi Loss-of-function Analysis and Imaging
Published on: October 3, 2017