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Intracellular distribution of transglutaminase activity during rat liver regeneration
Author(s) -
Remington John A.,
Russell Diane Haddock
Publication year - 1982
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041130211
Subject(s) - cycloheximide , tissue transglutaminase , cytoplasm , ornithine decarboxylase , liver regeneration , nucleus , biochemistry , biology , cell nucleus , microbiology and biotechnology , ornithine decarboxylase antizyme , intracellular , protein biosynthesis , enzyme , regeneration (biology)
Abstract Transglutaminase and ornithine decarboxylase activities have been assayed at intervals after partial hepatectomy in regenerating liver cells fractionated to obtain nuclear, cytoplasmic‐particulate, and cytoplasmic‐soluble fractions. Ornithine decarboxylase activity, localized entirely in the cytoplasmic fractions, undergoes a dramatic induction during the first 4 h after partial hepatectomy and remains elevated. This induction is very sensitive to inhibition by cycloheximide and actinomycin D, as previously reported. Transglutaminase activity is localized in both the cytoplasm and the nucleus with the highest specific activity in the nucleus. Nuclear transglutaminase activity approximately doubles in the first 2 h of liver regeneration, apparently as a result of a translocation of enzyme from the cytoplasm to the nucleus. Inhibitor studies indicate that the translocation is not dependent upon protein or RNA synthesis. In the first 2 h, actinomycin D slightly activates transglutaminase activity in the cytoplasmic‐particulate and nuclear fractions. Only at 4 h after the onset of regeneration do actinomycin D and cycloheximide show some inhibition of transglutaminase activity indicating de novo synthesis at this time. A broad increase of transglutaminase activity occurs from hours 12–16 to hour 32 after partial hepatectomy in the nuclear and cytoplasmic‐particulate fraction. These data suggest the existence of a function for transglutaminase in the nucleus of rat liver cells.