Biomaterial Database

Serial-section analysis of coated pits and vesicles involved in adsorptive pinocytosis in cultured fibroblasts. 1983

O W Petersen, and B van Deurs

We have examined, by analyzing thin (15-20 nm) serial sections, whether coated pits involved in adsorptive pinocytosis in cultured fibroblasts give rise to free coated vesicles or represent permanently surface-associated structures from the neck of which uncoated receptosomes pinch off and carry ligand into the cell. Human skin fibroblasts and mouse L-929 fibroblasts were incubated with cationized ferritin (CF), a ligand known to bind to coated pit regions, at 37 degrees C before fixation. In thin sections, CF was found in coated vesicular profiles within the cytoplasm. Serial sections revealed that whereas many of these coated profiles communicated with the cell surface, thus representing pits, about 10% in L-cells and 36% in skin fibroblasts were actually free coated vesicles. Moreover, evidence for uncoated vesicular structures (receptosomes) budding off from the coated pits was not obtained. We therefore conclude that coated pits do pinch off from the plasma membrane to form free, coated vesicles (pinosomes).

UI	MeSH Term	Description	Entries
D007739	L Cells	A cultured line of C3H mouse FIBROBLASTS that do not adhere to one another and do not express CADHERINS.	Earle's Strain L Cells,L Cell Line,L Cells (Cell Line),L-Cell Line,L-Cells,L-Cells, Cell Line,L929 Cell Line,L929 Cells,NCTC Clone 929 Cells,NCTC Clone 929 of Strain L Cells,Strain L Cells,Cell Line L-Cell,Cell Line L-Cells,Cell Line, L,Cell Line, L929,Cell Lines, L,Cell, L,Cell, L (Cell Line),Cell, L929,Cell, Strain L,Cells, L,Cells, L (Cell Line),Cells, L929,Cells, Strain L,L Cell,L Cell (Cell Line),L Cell Lines,L Cell, Strain,L Cells, Cell Line,L Cells, Strain,L-Cell,L-Cell Lines,L-Cell, Cell Line,L929 Cell,Strain L Cell
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D010873	Pinocytosis	The engulfing of liquids by cells by a process of invagination and closure of the cell membrane to form fluid-filled vacuoles.	Pinocytoses
D011992	Endosomes	Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.	Receptosomes,Endosome,Receptosome
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D003034	Coated Pits, Cell-Membrane	Specialized regions of the cell membrane composed of pits coated with a bristle covering made of the protein CLATHRIN. These pits are the entry route for macromolecules bound by cell surface receptors. The pits are then internalized into the cytoplasm to form the COATED VESICLES.	Bristle-Coated Pits,Cell-Membrane Coated Pits,Bristle Coated Pits,Bristle-Coated Pit,Cell Membrane Coated Pits,Cell-Membrane Coated Pit,Coated Pit, Cell-Membrane,Coated Pits, Cell Membrane,Pit, Bristle-Coated,Pit, Cell-Membrane Coated,Pits, Bristle-Coated,Pits, Cell-Membrane Coated
D005293	Ferritins	Iron-containing proteins that are widely distributed in animals, plants, and microorganisms. Their major function is to store IRON in a nontoxic bioavailable form. Each ferritin molecule consists of ferric iron in a hollow protein shell (APOFERRITINS) made of 24 subunits of various sequences depending on the species and tissue types.	Basic Isoferritin,Ferritin,Isoferritin,Isoferritin, Basic
D005347	Fibroblasts	Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.	Fibroblast
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000327	Adsorption	The adhesion of gases, liquids, or dissolved solids onto a surface. It includes adsorptive phenomena of bacteria and viruses onto surfaces as well. ABSORPTION into the substance may follow but not necessarily.	Adsorptions