Sequence of a second human asialoglycoprotein receptor: conservation of two receptor genes during evolution.

摘要: The asialoglycoprotein (ASGP) receptor isolated from human liver and the hepatoma cell line HepG2 migrates on NaDodSO4 gel electrophoresis as a single species of 45,000 daltons. Recently, we cDNA clone encoding this (H1) lambda gt11 library. From same library, have sequenced second ASGP receptor, H2, with protein sequence homology 58% to H1. There are two subspecies H2 that differ only by presence five-amino acid insertion in COOH-terminal extracytoplasmic domain. Comparison available sequences rat receptors R1 R2 indicates H1 is more homologous than similar Thus, genes evolved before separation man. As judged RNA blot hybridization using transcribed vitro clones standards, mRNA present equimolar amounts, each 0.005-0.01% total mRNA. This finding raises question whether three proteins functional heterodimers or they might serve different functions cell.