Molecular cloning of cDNA encoding a 55-kDa multifunctional thyroid hormone binding protein of skeletal muscle sarcoplasmic reticulum.

摘要: A cDNA clone encoding 55-kDa multifunctional, thyroid hormone binding protein of rabbit skeletal muscle sarcoplasmic reticulum was isolated and sequenced. The encoded a 509 amino acids, comparison the deduced acid sequence with NH2-terminal purified indicates that an 18-residue signal removed during synthesis. suggested this is related to human liver protein, rat disulfide isomerase, hepatoma beta-subunit prolyl 4-hydroxylase hen oviduct glycosylation site protein. contains two repeated sequences Trp-Cys-Gly-His-Cys-Lys proposed be in active sites isomerase. Northern blot analysis showed mRNA form present liver, kidney, brain, fast- slow-twitch muscle, myocardium. In all tissues reacts 2.7 kilobases length. multifunctional identified vesicles using monoclonal antibody specific from endoplasmic reticulum. mature Mr 56,681 95 acidic 61 basic acids. COOH-terminal highly enriched residues 17 last 29 acids being negatively charged. Analysis hydropathy suggests there are no potential transmembrane segments. Arg-Asp-Glu-Leu (RDEL), similar but different retention signal; Lys-Asp-Glu-Leu (KDEL) (Munro, S., Pelham, H.R.B. (1987) Cell 48, 899-907). This variant may function manner KDEL sequence, localize or positively charged Lys Arg thus interchange signal.