Abstract
Since its inception, electron microscopy (EM) has revealed that cellular membranes are organized into structurally distinct subdomains, created by localized protein and lipid assemblies to perform specific complex cellular functions. Caveolae are membrane subdomains that function as signaling platforms, endocytic carriers, sensors of membrane tension, and mechanical stress, as well as in lipid homeostasis. They were first discovered almost 60 years ago by pioneering electron microscopists. While new and exciting developments in SUPER-resolution fluorescent light microscopy facilitate studies of the spatial organization of fluorescently labeled protein components, these techniques cannot reveal the underlying cellular structures. Thus, equally exciting are developments in EM: genetically encoded probes for protein localization at sub-10 nm resolution, more powerful instruments that allow imaging of larger cell volumes, and computational methods for reconstructing three-dimensional images. Used in combination, as done by Ludwig et al. in the current issue of PLOS Biology, these tools reveal high-resolution insights into the composition and organization of the caveolae coat and the formation of these specialized structures. Together, these advances are contributing to a resurgence in EM.
Highlights
Cells communicate with each other and with their environment through dynamic signaling and trafficking events that occur at their outer surface, the plasma membrane
Perhaps the best characterized mediators of trafficking from the cell surface are clathrin coated vesicles (CCVs), which are responsible for the selective internalization of nutrients, signaling receptors, and transmembrane transporters to ensure vital metabolic activities of the cell
Because the clathrin coat is relatively stable, CCVs can be readily isolated by simple subcellular fractionation methods owing to their high density and small size
Summary
Cells communicate with each other and with their environment through dynamic signaling and trafficking events that occur at their outer surface, the plasma membrane. Caveolae, ‘‘little caves,’’ are another class of specialized internalizing structures, initially recognized in electron micrographs as smooth membrane invaginations with a characteristic bulb-like shape (Figure 1C) [6]. In addition to their role as endocytic carriers, caveolae are thought to function as static. Platforms for the spatial organization of signaling complexes, as mechanosensory devices, and in the regulation of lipid homeostasis (see [7] for recent review) Consistent with their diverse functions, the number and morphology of caveolae varies from tissue to tissue, and they are most abundant in endothelial cells and adipocytes.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
