Protein Degradation in Normal and Beige (Chediak-Higashi) Mice

Abstract

A B S T R A C T The beige mouse, C57BL/6 (bg/bg), is ain aniimal model for the Chediak-Higashi syndrome in main, a disease characterized morphologically by giant lysosomes in most cell types. Half-lives for the turnover of [14C]bicarbonate-labeled total soluble liver protein were determined in normal and beige mice. No significant differences were observed between the niormal and mutant strain for both rapidly and slowly turniing-over classes of proteins. Glucagon treatment durinig the time-course of protein degradation had simiiilar effects on both normal and mutant strains anid led to the conclusion that the rate of turnover of endogenous intracellular protein in the beige mouse liver does not differ from normal.The rates of uptake and degradation of an exogenous protein were determined in normal and beige mice by intravenously injecting 1251-bovine serum albumin and followinig, in peripheral blood, the loss with time of phosphotungstic acid-insoluble bovine serum albumin and the parallel appearance of phosphotungstic acid-soluble (degraded) material. No significant differences were observed between beige and normal mice in the uptake by liver lysosomes of 1251_ bovine serum albumin (t,/2 = 3.9 and 2.8 h, respectively). However, it was found that lysosomes from livers of beige mice released phosphotungstic acidsoluble radioactivity at a rate significantly slower than normal (t,2 = 6.8 and 3

Lysosomal Membranes from Beige Mice Contain Higher Than Normal Levels of Endoplasmic Reticulum Proteins

“…However, beta 2-macroglobulin was taken up and degraded at an apparently normal rate by both CHS or Beige cells, suggesting no abnormalities in receptor-mediated endocytosis . Additionally, no significant endogenous intracellular protein degradation defect was observed in Beige mouse fibroblasts …”

“…3 Additionally, no significant endogenous intracellular protein degradation defect was observed in Beige mouse fibroblasts. 4 The gene responsible for human CHS, encodes the LYST (Lysosomal Trafficking Regulator) protein, with molecular weight of 430 kDa, which is highly conserved in all species. 5 It has 87.9% amino acid identity with the mouse homologue.…”

The Coat Colors of Mice

“…Oliver, 1976), or ascorbate (Boxer et aI., 1976). For other investigations on the beige syndrome see Prieur et al (1972), Chi et al ( ,1976, Holland (1976), J. , Frankel et al (1978), GuyGrand et al (1978), Kaplan et al (1978), Lyons and Pitot (1978), and Swank and Brandt (1978). l3In addition to silver, Hagedoorn studied the interactions of a number of other coat-color factors.…”

Role of marrow-derived monocytes and mesangial cells in removal of immune complexes from renal glomeruli.

“…Mice. Since the CH mice are known to have decreased intraeellular bacterial killing and decreased uptake and degradation of soluble foreign proteins (10,11), disappearance of preformed immune complexes from the circulation was examined, using intact or reduced and alkylated antibodies. Groups of four CH mice were injected with preformed immune complexes, containing 5.0 mg of intact antibodies or 5.0 mg reduced and alkylated antibodies.…”