n-glycans are direct determinants of cftr folding and stability in secretory and endocytic membrane...
TRANSCRIPT
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
1/17
N-glycans are direct determinants of CFTRfolding and stability in secretory and
endocytic membrane traffic.Glozman R, Okiyoneda T, Mulvihill CM, Rini JM,Barriere H, Lukacs GL.
J Cell Biol . 2009 Mar 23;184(6):847-62.
S ergio UribeP rograma de Doctorado en Ciencias Mdicas
Facultad de Medicina
Universidad Austral de Chile
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
2/17
N-glycosylationposttranslational modificationsfolding, targeting, function °radation
cotranslational addition of glu3-man9-N-aga2 > Asn
N-glycosylation defect can severely impair thecell surface expression of membrane proteins
Rhodopsin retinitis pigmentosasulphonylurea receptor persistent hyperinsulinemic hypoglycemia
FGF receptor 2 craniosynostosis syndrome
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
3/17
Lack of glycosylation retard productive foldingby
preventing client protein engagement with the CNX/CRT
cyclesattenuate the metabolic stability at multiplecompartments, including the cell surface
Molecular basis of defective cell surface stability
of glycosylation-defective plasma membraneproteins is not known .
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
4/17
Cystic fibrosis transmembrane
conductance regulator (CFTR)
http://users.ox.ac.uk/~genemed/cysticfibrosis/protein.html http://users.ox.ac.uk/~genemed/cysticfibrosis/function.html
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
5/17
Although defective N-glycosylation impairs thefolding and stability of CFTR the complex-glycosylated CFTR expression level was
modestly reduced in CNX-depleted cellssuggesting that N-glycans may have anintrinsic role in the channel biogenesis .
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
6/17
N-glycosylationdefect reducesthe cell surfaceexpression of
CFTR
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
7/17
Defective N-glycosylation
severelyprevents theproductive
folding of CFTR
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
8/17
CNX knockdown partially inhibits CFTR folding
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
9/17
N-glycans are required for CFTR stability in post-Golgicompartments
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
10/17
Core glycosylation is sufficient for the foldingand stability of CFTR
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
11/17
Lysosomal targeting and inefficient endocytic recyclingaccount for the cell surface instability of glycosylation-
deficient CFTR
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
12/17
Ubiquitination acts as sorting signal directingglycosylation-deficient CFTR into lysosome
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
13/17
N-glycosylation increases the protease resistanceof the mature CFTR
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
14/17
N-glycosylation enhances the thermal stability of CFTR
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
15/17
Discusin
The direct chaperone-independent role of N-glycans in CFTR folding and stability
N-glycan folding effect on CFTR?N-glycans may alter the global stability of CFTR,displaying extensive domaindomain interactionsN-glycans limit the conformational space accessibleto the transmembrane segments, facilitatingposttranslational CFTR domain folding
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
16/17
Discusin
The cellular and molecular basis of the glycan-deficient CFTR instability at the plasmamembrane
Asp residue substitutions by itself?localized unfolding of the glycan-deficient channel initiates therecruitment of the cytosolic chaperone Ub system, leading to Ubconjugation and targeting the channel for proteolysis by the ELAD
folding energetic is a critical determinant of membraneprotein turnover not only at the early secretory pathway
paradigm of the 2D-CFTR degradation may serve as atestable model for the accelerated turnover of severalglycosylation-deficient plasma membrane proteins
-
8/6/2019 N-Glycans Are Direct Determinants of CFTR Folding and Stability in Secretory and Endocytic Membrane Traffic
17/17
The endoplasmic reticulumassociated Hsp40 DNAJB12 and Hsc70cooperate to facilitate RMA1 E3dependent degradation of nascentCFTR F508Grove et al., M ol Biol Cell . 2011 February 1; 22(3): 301314.
Glycosylation of CFTR is required for calnexin binding, and this modificationappears to be required for stabilization of transmembrane regions in MSD2 in theER membrane (Glozman et al., 2009
Quality control for unfolded proteins at the plasma membrane Apaja et al., J Cell Biol. 2010 November 1; 191(3): 553570.
Disease phenotype of a ferret CFTR-knockout model of cystic fibrosisSun et al., J Clin Invest. 2010 September 1; 120(9): 31493160.
Revisiting the Role of Cystic Fibrosis Transmembrane ConductanceRegulator and Counterion P ermeability in the pH Regulation of Endocytic OrganellesBarriere et al., M ol Biol Cell. 2009 July 1; 20(13): 31253141.