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Polyamine‐dependent alterations in the structure of microfilaments, golgi apparatus, endoplasmic reticulum, and proteoglycan synthesis in BHK cells
Author(s) -
Parkkinen Jyrki J.,
Lammi Mikko J.,
Ågren Ulla,
Tammi Markku,
Keinänen Tuomo A.,
Hyvönen Tapani,
Eloranta Terho O.
Publication year - 1997
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(19970801)66:2<165::aid-jcb4>3.0.co;2-o
Subject(s) - endoplasmic reticulum , golgi apparatus , microbiology and biotechnology , biochemistry , chemistry , wheat germ agglutinin , biology , lectin
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, α‐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 β‐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 [ 3 H]glucosamine and [ 35 S]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. J. Cell Biochem. 66:165‐174, 1997. © 1997 Wiley‐Liss, Inc.