caa a22 4500 397494556 CHVBK 20180308164517.0 cr unu---uuuuu 161202e199508 xx s 000 0 eng 10.1093/oxfordjournals.jbchem.a124920 doi (NATIONALLICENCE)oxford-10.1093/oxfordjournals.jbchem.a124920 Malfolded Cytochrome P-450(M1) Localized in Unusual Membrane Structures of the Endoplasmic Reticulum in Cultured Animal Cells [Elektronische Daten] [Naotada Ishihara, Shohei Yamashine, Masao Sakaguchi, Katsuyoshi Mihara, Tsuneo Omura] A conserved region containing three to five proline residues is present just behind the signal-anchor sequence in the amino terminal portion of most microsomal cytochrome P-450s. We have shown that the proline residues are crucial for correct folding in Schizosaccharomyces pombe cells by using mutants of P-450(M1) in which one to three of the proline residues were changed to alanine. To examine the effects of the mutations on the intracellular localization of P-450s, they were expressed in COS-7 cells. They were found to be localized only in the perinuclear loci as patched structures like the Golgi apparatus, while the wild-type P-450(M1) is localized in the reticular structures which are typical for the ER membrane. However, treatment of the cells with Brefeldin A had no effect on the patched structures. Upon co-expression with another ER membrane protein, CD4D, which possesses a double lysine motif, the expressed CD4D was localized not only in the patched structures as the mutated P-450(M1)s, but also in the reticular structures of ER. When the cells were homogenized and then fractionated, the mutated P-450(M1) was recovered mainly in the low-speed precipitate and in the fractions of much higher density than the normal ER membrane. On electron microscopic observation, unusual membranous bodies were observed near the nucleus only when the mutated P-450(M1) was expressed. From these results, we suggest that the P-450(M1) molecules which failed to take on the correct conformation became aggregated on the ER membrane and were localized in the perinuclear region forming membrane bodies composed of small vesicles derived from the ER membranes in the cells. © by the Journal of Biochemistry Regular Papers nationallicence COS-7 nationallicence cytochrome P-450 nationallicence endoplasmic reticulum nationallicence malfolded protein nationallicence membrane protein nationallicence Ishihara Naotada Department of Molecular Biology, Graduate School of Medical Science, Kyushu University Higashi-ku, Fukuoka 812 aut Yamashine Shohei Department of Anatomy, Kitasato University School of Medicine Sagamihara 228 aut Sakaguchi Masao Department of Molecular Biology, Graduate School of Medical Science, Kyushu University Higashi-ku, Fukuoka 812 aut Mihara Katsuyoshi Department of Molecular Biology, Graduate School of Medical Science, Kyushu University Higashi-ku, Fukuoka 812 aut Omura Tsuneo Department of Molecular Biology, Graduate School of Medical Science, Kyushu University Higashi-ku, Fukuoka 812 aut The Journal of Biochemistry Oxford University Press 118/2(1995-08), 397-404 0021-924X 118:2<397 1995 118 jbchem https://doi.org/10.1093/oxfordjournals.jbchem.a124920 text/html Onlinezugriff via DOI 1 other jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.jbchem.a124920 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ishihara Naotada Department of Molecular Biology, Graduate School of Medical Science, Kyushu University Higashi-ku, Fukuoka 812 aut NATIONALLICENCE 700 1- Yamashine Shohei Department of Anatomy, Kitasato University School of Medicine Sagamihara 228 aut NATIONALLICENCE 700 1- Sakaguchi Masao Department of Molecular Biology, Graduate School of Medical Science, Kyushu University Higashi-ku, Fukuoka 812 aut NATIONALLICENCE 700 1- Mihara Katsuyoshi Department of Molecular Biology, Graduate School of Medical Science, Kyushu University Higashi-ku, Fukuoka 812 aut NATIONALLICENCE 700 1- Omura Tsuneo Department of Molecular Biology, Graduate School of Medical Science, Kyushu University Higashi-ku, Fukuoka 812 aut NATIONALLICENCE 773 0- The Journal of Biochemistry Oxford University Press 118/2(1995-08), 397-404 0021-924X 118:2<397 1995 118 jbchem Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford