Abstract
The mammalian Golgi complex is comprised of a ribbon of stacked cisternal membranes often located in the pericentriolar region of the cell. Here, we report that during apoptosis the Golgi ribbon is fragmented into dispersed clusters of tubulo-vesicular membranes. We have found that fragmentation is caspase dependent and identified GRASP65 (Golgi reassembly and stacking protein of 65 kD) as a novel caspase substrate. GRASP65 is cleaved specifically by caspase-3 at conserved sites in its membrane distal COOH terminus at an early stage of the execution phase. Expression of a caspase-resistant form of GRASP65 partially preserved cisternal stacking and inhibited breakdown of the Golgi ribbon in apoptotic cells. Our results suggest that GRASP65 is an important structural component required for maintenance of Golgi apparatus integrity.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Chloromethyl Ketones / pharmacology
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Apoptosis / physiology*
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Autoantigens
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Caspase 3
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Caspases / metabolism*
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Enzyme Inhibitors / pharmacology
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Glycoproteins*
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Golgi Apparatus / enzymology*
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Golgi Apparatus / ultrastructure*
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Golgi Matrix Proteins
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Green Fluorescent Proteins
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HeLa Cells
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Humans
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Luminescent Proteins / genetics
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Membrane Glycoproteins / metabolism
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Membrane Proteins / metabolism*
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Microscopy, Electron
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Microscopy, Fluorescence
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Microscopy, Video
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N-Acetylgalactosaminyltransferases / metabolism
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Oligopeptides / pharmacology
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Peptide Hydrolases / metabolism*
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Polypeptide N-acetylgalactosaminyltransferase
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Proteins / metabolism
Substances
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Amino Acid Chloromethyl Ketones
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Autoantigens
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Enzyme Inhibitors
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GORASP1 protein, human
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Glycoproteins
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Golgi Matrix Proteins
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Golgin subfamily A member 2
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Luminescent Proteins
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Membrane Glycoproteins
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Membrane Proteins
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Oligopeptides
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Proteins
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TGOLN2 protein, human
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aspartyl-glutamyl-valyl-aspartal
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benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
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Green Fluorescent Proteins
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N-Acetylgalactosaminyltransferases
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Peptide Hydrolases
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CASP3 protein, human
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Caspase 3
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Caspases