Matrix proteins can generate the higher order architecture of the Golgi apparatus.
The Golgi apparatus in animal cells comprises a reticulum of linked stacks in the pericentriolar and often in the juxtanuclear regions of the cell. The unique architecture of this organelle is thought to depend on the cytoskeleton and cytoplasmic matrix proteins--the best characterized being the golgin family of fibrous, coiled-coil proteins and the GRASP family of stacking proteins. Here we show that these matrix proteins can be separated from oligosaccharide-modifying enzymes in the Golgi stack without affecting their ability to form a ribbon-like reticulum in the correct location near to the nucleus. Our data suggest that the Golgi is a structural scaffold that can exist independently of, but is normally populated by, the enzyme-containing membranes that modify transiting cargo. This new concept of the Golgi further indicates that the Golgi may be an autonomous organelle rather than one that is in simple dynamic equilibrium with the endoplasmic reticulum.
Seemann
J
J
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520-8002, USA.
Jokitalo
E
E
Pypaert
M
M
Warren
G
G
D000818:Animals; D001324:Autoantigens; D020126:Brefeldin A / Q000494:pharmacology; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000302:isolation & purification / Q000502:physiology*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006056:Golgi Apparatus / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure*; D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure; D008361:Mannosidases / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D020559:Monomeric GTP-Binding Proteins / Q000494:pharmacology; D021381:Protein Transport; D051381:Rats; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D043323:alpha-Mannosidase
D001324:Autoantigens; D003598:Cytoskeletal Proteins; C097741:Golgin subfamily A member 2; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D020126:Brefeldin A; D008361:Mannosidases; D043323:alpha-Mannosidase; D020559:Monomeric GTP-Binding Proteins; C077395:SAR1 protein, S cerevisiae