A conserved region of the R domain of cystic fibrosis transmembrane conductance regulator is important in processing and function
| Autor: | Ling Jun Huan, Xenia K. Morin, Yanchun Wang, Peter R. Zeman, Christine E. Bear, Eva A. Pasyk, Elizabeth Garami, Kevin Galley |
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| Rok vydání: | 1998 |
| Předmět: |
Cystic Fibrosis
Molecular Sequence Data Cystic Fibrosis Transmembrane Conductance Regulator ATP-binding cassette transporter Sequence alignment Kidney Transfection Biochemistry Conserved sequence Cell Line Membrane Potentials Mice Xenopus laevis Serine Animals Humans Point Mutation ATP Binding Cassette Transporter Subfamily B Member 1 Amino Acid Sequence Phosphorylation Molecular Biology Peptide sequence Conserved Sequence Chloride channel activity biology Sequence Homology Amino Acid Cell Membrane Cell Biology Cystic fibrosis transmembrane conductance regulator Recombinant Proteins Cell biology Cyclic nucleotide-binding domain Chloride channel biology.protein Mutagenesis Site-Directed Oocytes Female Ion Channel Gating Sequence Alignment |
| Zdroj: | The Journal of biological chemistry. 273(48) |
| ISSN: | 0021-9258 |
| Popis: | The R domain of cystic fibrosis transmembrane conductance regulator (CFTR) connects the two halves of the protein, each of which possess a transmembrane-spanning domain and a nucleotide binding domain. Phosphorylation of serine residues, which reside mostly within the C-terminal two-thirds of the R domain, is required for nucleotide-dependent activation of CFTR chloride channel activity. The N terminus of the R domain is also likely to be important in CFTR function, since this region is highly conserved among CFTRs of different species and exhibits sequence similarity with the "linker region" of the related protein, P-glycoprotein. To date, however, the role of this region in CFTR channel function remains unknown. In this paper, we report the effects of five disease-causing mutations within the N terminus of the CFTR-R domain. All five mutants exhibit defective protein processing in mammalian HEK-293 cells, suggesting that they are mislocalized and fail to reach the cell surface. However, in the Xenopus oocyte, three mutants reached the plasma membrane. One of these mutants, L619S, exhibits no detectable function, whereas the other two, D614G and I618T, exhibit partial activity as chloride channels. Single channel analysis of these latter two mutants revealed that they possess defective rates of channel opening, consistent with the hypothesis that the N terminus of the R domain participates in ATP-dependent channel gating. These findings support recent structural models that include this region within extended boundaries of the first nucleotide binding domain. |
| Databáze: | OpenAIRE |
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