Complexity in the secretory pathway: The assembly and secretion of apolipoprotein B-containing lipoproteins

Abstract

ApoB is essential for the production of hepatic atherogenic lipoproteins. The major role of post-transcriptional degradation of apoB is surprising. The same lipophilic sequences enabling apoB to partake in lipoprotein formation also appear to participate in its targeting to proteasomal degradation when lipid export by the liver is not favored. Even after the translocation of nascent apoB is completed, several quality controls appear to be in place to further regulate lipoprotein secretion. Indeed, the cellular "bureaucracy" developed to regulate apoB lipoprotein assembly and secretion matches the complexity of the lipoprotein itself.