Role of the C-termini of human and chicken plasma retinol-binding proteins
Natarajan, V.; Smeland, S.; Moskaug, J.O.; Kamiyama, S.; Masushige, S.; Kato, S.; Blomhoff, R.
European Journal of Cell Biology 73(4): 316-320
1997
ISSN/ISBN: 0171-9335 PMID: 9270874 Document Number: 482438
The most prominent differences between mammalian and non-mammalian vertebrate retinol-binding proteins (RBP) are in the C-terminal sequences. We have cloned and sequenced the cDNA for chicken RBP. Transfected COS cells that transiently expressed mammalian (human) or non-mammalian (chicken) RBP were used to demonstrate that both proteins were able to bind retinol and human trans-thyretin. However, we observed an increased retinol-independent secretion in cells expressing chicken RBP and reduced ligand-dependent secretion compared to the human protein. It can therefore be concluded that the C-terminal amino acid tail which is missing in chicken RBP compared to human RBP might play a role in retention and ligand-induced secretion.