Polyamine-dependent alterations in the structure of microfilaments, Golgi apparatus, endoplasmic reticulum, and proteoglycan synthesis in BHK cells.
J Cell Biochem
; 66(2): 165-74, 1997 Aug 01.
Article
em En
| MEDLINE
| ID: mdl-9213218
ABSTRACT
The activity of ornithine decarboxylase, the key enzyme in the synthesis of polyamines, is essential for proliferation and differentiation of all living cells. Two inhibitors of ornithine decarboxylase, alpha-difluoromethylornithine (DFMO) and 1-aminooxy-3-aminopropane (APA), caused swelling of endoplasmic reticulum (ER) and medial and trans Golgi cisternae, and the disappearance of stress fibers, as visualized by staining with fluorescent concanavalin A (ConA), C6-NBD-ceramide or wheat germ agglutinin (WGA), and phalloidin, respectively. In contrast, the pattern of microtubules, stained with a beta-tubulin antibody, was not affected. Rough ER seemed to be especially affected in polyamine deprivation forming whorls and involutions, which were observed by transmission electron microscopy. Since ER and Golgi apparatus are vital parts of the glycosylation and secretory machinery of the cell, we tested the ability of these structurally altered cell organelles to synthesize proteoglycans using [3H]glucosamine and [35S]sulfate as precursors. The total incorporation rate into proteoglycans and hyaluronan was not reduced in polyamine-deprived cells, suggesting that the total glycosylation capacity of cells was not affected. However, the synthesis of a high molecular weight proteoglycan containing chondroitin and keratan sulfate was completely inhibited. The remodeling of cytoskeleton and rough endoplasmic reticulum in polyamine deprivation may perturb the synthesis and secretion of the components of membrane skeleton and of the extracellular matrix, e.g., proteoglycans. Rough ER and cytoskeleton may be the targets where polyamines affect cell proliferation and differentiation.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteoglicanas
/
Citoesqueleto de Actina
/
Poliaminas Biogênicas
/
Retículo Endoplasmático
/
Complexo de Golgi
Limite:
Animals
Idioma:
En
Ano de publicação:
1997
Tipo de documento:
Article