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Structural cues involved in endoplasmic reticulum degradation of G85E and G91R mutant cystic fibrosis transmembrane conductance regulator.
Xiong X, Bragin A, Widdicombe JH, Cohn J, Skach WR.
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Abnormal folding of mutant cystic fibrosis transmembrane conductance regulator (CFTR) and subsequent degradation in the endoplasmic reticulum is the basis for most cases of cystic fibrosis. Structural differences between wild-type (WT) and mutant proteins, however, remain unknown. Here we examine the intracellular trafficking, degradation, and transmembrane topology of two mutant CFTR proteins, G85E and G91R, each of which contains an additional charged residue within the first putative transmembrane helix (TM1). In microinjected Xenopus laevis oocytes, these mutations markedly disrupted CFTRplasma membrane chloride channel activity. G85E and G91R mutants (but not a conservative mutant, G91A) failed to acquire complex N-linked carbohydrates, and were rapidly degraded before reaching the Golgi complex thus exhibiting a trafficking phenotype similar to DeltaF508 CFTR. Topologic analysis revealed that neither G85E nor G91R mutations disrupted CFTR NH2 terminus transmembrane topology. Instead, WT as well as mutant TM1 spanned the membrane in the predicted C-trans (type II) orientation, and residues 85E and 91R were localized within or adjacent to the plane of the lipid bilayer. To understand how these charged residues might provide structural cues for ER degradation, we examined the stability of WT, G85E, and G91R CFTR proteins truncated at codons 188, 393, 589, or 836 (after TM2, TM6, the first nucleotide binding domain, or the R domain, respectively). These results indicated that G85E and G91R mutations affected CFTR folding, not by gross disruption of transmembrane assembly, but rather through insertion of a charged residue within the plane of the bilayer, which in turn influenced higher order tertiary structure.
Adams,
Incorporation of a charged amino acid into the membrane-spanning domain blocks cell surface transport but not membrane anchoring of a viral glycoprotein.
1985, Pubmed
Adams,
Incorporation of a charged amino acid into the membrane-spanning domain blocks cell surface transport but not membrane anchoring of a viral glycoprotein.
1985,
Pubmed Akabas,
Amino acid residues lining the chloride channel of the cystic fibrosis transmembrane conductance regulator.
1994,
Pubmed
,
Xenbase Anderson,
Demonstration that CFTR is a chloride channel by alteration of its anion selectivity.
1991,
Pubmed BARTH,
Differentiation of cells of the Rana pipiens gastrula in unconditioned medium.
1959,
Pubmed Bear,
Cl- channel activity in Xenopus oocytes expressing the cystic fibrosis gene.
1991,
Pubmed
,
Xenbase Bibi,
Organization and stability of a polytopic membrane protein: deletion analysis of the lactose permease of Escherichia coli.
1991,
Pubmed Bibi,
The N-terminal 22 amino acid residues in the lactose permease of Escherichia coli are not obligatory for membrane insertion or transport activity.
1992,
Pubmed Blobel,
Intracellular protein topogenesis.
1980,
Pubmed Bonifacino,
Colocalized transmembrane determinants for ER degradation and subunit assembly explain the intracellular fate of TCR chains.
1990,
Pubmed Bonifacino,
A peptide sequence confers retention and rapid degradation in the endoplasmic reticulum.
1990,
Pubmed Brown,
Chemical chaperones correct the mutant phenotype of the delta F508 cystic fibrosis transmembrane conductance regulator protein.
1996,
Pubmed Calamia,
Membrane protein spanning segments as export signals.
1992,
Pubmed Carroll,
Alternate translation initiation codons can create functional forms of cystic fibrosis transmembrane conductance regulator.
1995,
Pubmed
,
Xenbase Chalkley,
A cystic fibrosis patient who is homozygous for the G85E mutation has very mild disease.
1991,
Pubmed Chang,
Mapping of cystic fibrosis transmembrane conductance regulator membrane topology by glycosylation site insertion.
1994,
Pubmed Cheng,
Defective intracellular transport and processing of CFTR is the molecular basis of most cystic fibrosis.
1990,
Pubmed Cohn,
Characterization of the cystic fibrosis transmembrane conductance regulator in a colonocyte cell line.
1992,
Pubmed Davis,
A charged amino acid substitution within the transmembrane anchor of the Rous sarcoma virus envelope glycoprotein affects surface expression but not intracellular transport.
1987,
Pubmed Denning,
Processing of mutant cystic fibrosis transmembrane conductance regulator is temperature-sensitive.
1992,
Pubmed
,
Xenbase Denning,
Localization of cystic fibrosis transmembrane conductance regulator in chloride secretory epithelia.
1992,
Pubmed Drumm,
Chloride conductance expressed by delta F508 and other mutant CFTRs in Xenopus oocytes.
1991,
Pubmed
,
Xenbase Guillermit,
A novel mutation in exon 3 of the CFTR gene.
1993,
Pubmed Hartman,
Recombinant synthesis, purification, and nucleotide binding characteristics of the first nucleotide binding domain of the cystic fibrosis gene product.
1992,
Pubmed Hartmann,
Predicting the orientation of eukaryotic membrane-spanning proteins.
1989,
Pubmed Hasegawa,
A multifunctional aqueous channel formed by CFTR.
1992,
Pubmed
,
Xenbase Higgins,
ABC transporters: from microorganisms to man.
1992,
Pubmed Hyde,
Structural model of ATP-binding proteins associated with cystic fibrosis, multidrug resistance and bacterial transport.
1990,
Pubmed Jensen,
Multiple proteolytic systems, including the proteasome, contribute to CFTR processing.
1995,
Pubmed Klausner,
Protein degradation in the endoplasmic reticulum.
1990,
Pubmed Lippincott-Schwartz,
Degradation from the endoplasmic reticulum: disposing of newly synthesized proteins.
1988,
Pubmed Lukacs,
Conformational maturation of CFTR but not its mutant counterpart (delta F508) occurs in the endoplasmic reticulum and requires ATP.
1994,
Pubmed Marino,
Localization of the cystic fibrosis transmembrane conductance regulator in pancreas.
1991,
Pubmed Ohrui,
Radiotracer studies of cystic fibrosis transmembrane conductance regulator expressed in Xenopus oocytes.
1994,
Pubmed
,
Xenbase Pasyk,
Mutant (delta F508) cystic fibrosis transmembrane conductance regulator Cl- channel is functional when retained in endoplasmic reticulum of mammalian cells.
1995,
Pubmed Pind,
Participation of the endoplasmic reticulum chaperone calnexin (p88, IP90) in the biogenesis of the cystic fibrosis transmembrane conductance regulator.
1994,
Pubmed Reisin,
The cystic fibrosis transmembrane conductance regulator is a dual ATP and chloride channel.
1994,
Pubmed Riordan,
Identification of the cystic fibrosis gene: cloning and characterization of complementary DNA.
1989,
Pubmed Rothman,
Construction of defined polytopic integral transmembrane proteins. The role of signal and stop transfer sequence permutations.
1988,
Pubmed
,
Xenbase Sato,
Glycerol reverses the misfolding phenotype of the most common cystic fibrosis mutation.
1996,
Pubmed Sheppard,
The amino-terminal portion of CFTR forms a regulated Cl- channel.
1994,
Pubmed Skach,
Transmembrane orientation and topogenesis of the third and fourth membrane-spanning regions of human P-glycoprotein (MDR1).
1994,
Pubmed
,
Xenbase Skach,
Amino-terminal assembly of human P-glycoprotein at the endoplasmic reticulum is directed by cooperative actions of two internal sequences.
1993,
Pubmed Skach,
Evidence for an alternate model of human P-glycoprotein structure and biogenesis.
1993,
Pubmed
,
Xenbase Thomas,
The cystic fibrosis transmembrane conductance regulator. Effects of the most common cystic fibrosis-causing mutation on the secondary structure and stability of a synthetic peptide.
1992,
Pubmed Wahle,
Membrane topology of the high-affinity L-glutamate transporter (GLAST-1) of the central nervous system.
1996,
Pubmed
,
Xenbase Walter,
Preparation of microsomal membranes for cotranslational protein translocation.
1983,
Pubmed Ward,
Intracellular turnover of cystic fibrosis transmembrane conductance regulator. Inefficient processing and rapid degradation of wild-type and mutant proteins.
1994,
Pubmed Ward,
Degradation of CFTR by the ubiquitin-proteasome pathway.
1995,
Pubmed Welsh,
Molecular mechanisms of CFTR chloride channel dysfunction in cystic fibrosis.
1993,
Pubmed Yang,
The common variant of cystic fibrosis transmembrane conductance regulator is recognized by hsp70 and degraded in a pre-Golgi nonlysosomal compartment.
1993,
Pubmed Zielenski,
Identification of mutations in exons 1 through 8 of the cystic fibrosis transmembrane conductance regulator (CFTR) gene.
1991,
Pubmed
