Role of the C-termini of human and chicken plasma retinol-binding proteins.
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 transthyretin. 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.
Natarajan
V
V
Institute for Nutrition Research, University of Oslo, Blindern, Norway.
Smeland
S
S
Moskaug
J O
JO
Kamiyama
S
S
Masushige
S
S
Kato
S
S
Blomhoff
R
R
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002645:Chickens; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004721:Endoplasmic Reticulum; D006801:Humans; D008024:Ligands; D011228:Prealbumin / Q000378:metabolism*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins; D012177:Retinol-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D054839:Retinol-Binding Proteins, Plasma; D017422:Sequence Analysis, DNA; D014801:Vitamin A / Q000378:metabolism*
D018076:DNA, Complementary; D008024:Ligands; D011228:Prealbumin; D011993:Recombinant Fusion Proteins; D012177:Retinol-Binding Proteins; D054839:Retinol-Binding Proteins, Plasma; D014801:Vitamin A