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BiP expression is not increased by the accumulation of PiZ α 1 ‐antitrypsin in the endoplasmic reticulum
Author(s) -
Cresteil Danièle,
Ciccarelli Ernesto,
Soni Théophile,
Alonso Maria A.,
Jacobs Paul,
Bollen Alex,
Alvarez Fernando
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80944-e
Subject(s) - endoplasmic reticulum , subcellular localization , messenger rna , western blot , secretion , northern blot , microbiology and biotechnology , transfection , biology , secretory protein , stim1 , secretory pathway , chemistry , golgi apparatus , biochemistry , gene , cytoplasm
PiZ, a mutant human α 1 ‐antitrypsin, is associated with liver and pulmonary disease and is characterized by defective secretion and accumulation of the protein in the endoplasmic reticulum. We tested the hypothesis that BiP (a protein that binds newly synthesized protein in the endoplasmic reticulum, prevents secretion of incorrectly folded protein, and solubilizes protein aggregates), could play a part in the retention of PiZ α 1 ‐antitrypsin in the endoplasmic reticulum. Subcellular fractions from PiM (normal) and PiZ livers were prepared and analyzed by immunoblotting. No increase of BiP was detected in the PiZ liver. In addition, when total RNA from the same livers were analyzed by slot and Northern blot hybridization, no difference was found in the level of BiP mRNA between PiM and PiZ livers. Similar results were found in clones of CHO and MDCK cells transfected with PiM of PiZ α 1 ‐antitrypsin cDNAs. These results indicate that BiP does not play a part in the retention of PiZ α 1 ‐antitrypsin and suggest that PiZ protein is not misfolded.