Riboflavin deficiency impairs oxidative folding and secretion of apolipoprotein B-100 in HepG2 cells, triggering stress response systems.

ABSTRACT: Secretory proteins such as apolipoprotein B-100 (apoB) undergo oxidative folding (formation of disulfide bonds) in the endoplasmic reticulum (ER) before secretion. Oxidative folding depends on flavoproteins in eukaryotes. Here, human liver (HepG2) cells were used to model effects of riboflavin concentrations in culture media on folding and secretion of apoB. Cells were cultured in media containing 3.1, 12.6, and 300 nmol/L of riboflavin, representing moderately deficient, physiological, and pharmacological plasma concentrations in humans, respectively. When cells were cultured in riboflavin-deficient medium, secretion of apoB decreased by >80% compared with controls cultured in physiological medium. The nuclear translocation of the transcription factor ATF-6 increased by >180% in riboflavi

SUBMITTER: Manthey KC 

PROVIDER: S-EPMC1201499 | biostudies-literature | 2005 May

REPOSITORIES: biostudies-literature