PMID- 18230692
OWN - NLM
STAT- MEDLINE
DCOM- 20080422
LR  - 20131121
IS  - 1521-0103 (Electronic)
IS  - 0022-3565 (Linking)
VI  - 325
IP  - 1
DP  - 2008 Apr
TI  - Proteasome-dependent pharmacological rescue of cystic fibrosis transmembrane 
      conductance regulator revealed by mutation of glycine 622.
PG  - 89-99
LID - 10.1124/jpet.107.134502 [doi]
AB  - The most common mutation (F508del) causing cystic fibrosis (CF) results in 
      misfolding of the CF transmembrane conductance regulator (CFTR), leading to its 
      degradation via the proteasome pathway. To study the mechanism of action of 
      several pharmacological chaperones benzo[c]quinolizinium (MPB), we analyzed their 
      effects on two CF mutations; F508del-CFTR and G622D-CFTR. The replacement of 
      Gly622 by an aspartic acid (G622D) alters the trafficking and activity of the 
      protein. G622D, similar to F508del, was functionally rescued by the glucosidase 
      inhibitor miglustat but, unlike F508del, could not be rescued by MPB. A 
      structure-activity relationship for F508del functional correction revealed the 
      following profile: MPB-104-91-07-80 > 05 > 89 >> 9-hydroxyphenanthrene = 
      phenanthrene. Coimmunoprecipitation experiments on human airway epithelial 
      F508del/F508del CF15 cells showed that MPB did not prevent the interaction of 
      F508del-CFTR with heat shock protein (HSP)70, HSP90, or calnexin. Functional 
      rescue of F508del-CFTR by MPB and miglustat was abolished by brefeldin A (BFA) 
      but potentiated by thapsigargin (TG) and geldanamycin. The proteasome inhibitor 
      MG132 potentiated the effect of miglustat but only modestly affected that of MPB. 
      It is noteworthy that MPB inhibited proteasome activity in 
      F508del-CFTR-expressing cells but did not directly affect the activity of 
      purified 20S proteasome. With the mutant G622D-CFTR, MPB did not inhibit 
      proteasome activity, as in mock-transfected cells. Inhibition of cellular 
      degradation machinery by MPB is not only CFTR-dependent, but it also follows 
      similar structure-activity relationship as demonstrated by functional correction. 
      We conclude that G622D is a partial trafficking-deficient mutant with 
      dysfunctional chloride channel activity, and that Gly622 is part of the putative 
      site for interaction of MPB with CFTR, protecting the channel from 
      proteasome-mediated degradation.
FAU - Norez, Caroline
AU  - Norez C
AD  - Institut de Physiologie et Biologie Cellulaires, Universite de Poitiers, Centre 
      National de la Recherche Scientifique, 86022 Poitiers, France. 
      caroline.norez@univ-poitiers.fr
FAU - Bilan, Frederic
AU  - Bilan F
FAU - Kitzis, Alain
AU  - Kitzis A
FAU - Mettey, Yvette
AU  - Mettey Y
FAU - Becq, Frederic
AU  - Becq F
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20080129
PL  - United States
TA  - J Pharmacol Exp Ther
JT  - The Journal of pharmacology and experimental therapeutics
JID - 0376362
RN  - 0 (5-butyl-7-chloro-6-hydroxybenzo(c)quinolizinium)
RN  - 0 (6-hydroxy-10-chlorobenzo(c)quinolizinium)
RN  - 0 (Quinolizines)
RN  - 126880-72-6 (Cystic Fibrosis Transmembrane Conductance Regulator)
RN  - EC 3.4.25.1 (Proteasome Endopeptidase Complex)
RN  - TE7660XO1C (Glycine)
SB  - IM
MH  - Binding Sites
MH  - Cell Line
MH  - Cystic Fibrosis Transmembrane Conductance Regulator/*genetics
MH  - Glycine/*genetics
MH  - Humans
MH  - *Mutation
MH  - Proteasome Endopeptidase Complex/drug effects/*metabolism
MH  - Protein Transport
MH  - Quinolizines/*pharmacology
MH  - Structure-Activity Relationship
EDAT- 2008/01/31 09:00
MHDA- 2008/04/23 09:00
CRDT- 2008/01/31 09:00
PHST- 2008/01/31 09:00 [pubmed]
PHST- 2008/04/23 09:00 [medline]
PHST- 2008/01/31 09:00 [entrez]
AID - jpet.107.134502 [pii]
AID - 10.1124/jpet.107.134502 [doi]
PST - ppublish
SO  - J Pharmacol Exp Ther. 2008 Apr;325(1):89-99. doi: 10.1124/jpet.107.134502. Epub 
      2008 Jan 29.