en
Scientific article
English

Effect of phalloidin on liver actin distribution, content, and turnover

Published inJournal of cellular biochemistry, vol. 20, no. 4, p. 393-407
Publication date1982
Abstract

Phalloidin increases F-actin microfilament content and actin-directed immunofluorescence in hepatocytes in vivo and also increases actin polymerization and the stability of F-actin in vitro. We studied the sensitivity of immunofluorescent staining of actin to an actin depolymerizing factor (ADF) as well as actin content, degree of polymerization, and turnover in livers of in vivo phalloidin-treated rats. Pretreatment with ADF abolished anti-actin antibody (AAA) staining of normal liver but did not modify staining of livers from phalloidin-treated animals. Planimetric analyses of SDS-polyacrylamide gels showed the percent actin of total protein was increased by approximately 40% and the absolute amount of actin by approximately 43%, ten days after daily phalloidin treatment (50 micrograms/100 gm body weight). Similar but smaller changes could be seen after one day of treatment. Ultracentrifugational analyses of liver extracts indicated no change in the amount or proportion of G-actin but a 194% increase in the proportion of F-actin in ten-day treated animals, changes also apparent in one day animals. Neither the relative fractional rate of actin synthesis nor its synthesis as a percent of total protein synthesis was altered either at one-day or ten-day post-phalloidin treatment. Dualisotope experiments indicated that the rate of actin degradation was decreased selectively in the one- to three-day period following drug treatment. Thus, phalloidin appears to stabilize actin against the depolymerizing actions of ADF, increases the proportion of F-actin without altering the size of the G-actin pool, and causes accumulation of actin by decreasing its relative rate of degradation.

Keywords
  • Actin Depolymerizing Factors
  • Actins/analysis/biosynthesis/ metabolism
  • Animals
  • Destrin
  • Fluorescent Antibody Technique
  • Liver/drug effects/ metabolism
  • Male
  • Microfilament Proteins
  • Oligopeptides/ pharmacology
  • Phalloidine/ pharmacology
  • Proteins/pharmacology
  • Rats
  • Rats, Inbred Strains
Citation (ISO format)
LOW, R. B. et al. Effect of phalloidin on liver actin distribution, content, and turnover. In: Journal of cellular biochemistry, 1982, vol. 20, n° 4, p. 393–407. doi: 10.1002/jcb.1982.240200409
Identifiers
ISSN of the journal0730-2312
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