Processing of CFTR: traversing the cellular maze--how much CFTR needs to go through to avoid cystic fibrosis?
Biosynthesis of the cystic fibrosis transmembrane conductance regulator (CFTR), like other proteins aimed at the cell surface, involves transport through a series of membranous compartments, the first of which is the endoplasmic reticulum (ER), where CFTR encounters the appropriate environment for folding, oligomerization, maturation, and export from the ER. After exiting the ER, CFTR has to traffic through complex pathways until it reaches the cell surface. Although not yet fully understood, the fine details of these pathways are starting to emerge, partially through identification of an increasing number of CFTR-interacting proteins (CIPs) and the clarification of their roles in CFTR trafficking and function. These aspects of CFTR biogenesis/degradation and by membrane traffic and CIPs are discussed in this review. Following this description of complex pathways and multiple checkpoints to which CFTR is subjected in the cell, the basic question remains of how much CFTR has to overcome these barriers and be functionally expressed at the plasma membrane to avoid CF. This question is also discussed here.
Amaral
Margarida D
MD
Department of Chemistry and Biochemistry, Faculty of Sciences, University of Lisbon, and Centre of Human Genetics, National Institute of Health Dr. Ricardo Jorge, Lisbon, Portugal. mdamaral@fc.ul.pt
D000595:Amino Acid Sequence; D037281:Calnexin / Q000378:metabolism; D003550:Cystic Fibrosis / Q000378:metabolism* / Q000517:prevention & control*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism*; D005260:Female; D006801:Humans; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000378:metabolism; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000378:metabolism; D017510:Protein Folding; D021381:Protein Transport; D012016:Reference Values
C505032:CFTR protein, human; D009419:Nerve Tissue Proteins; D011257:Pregnancy Proteins; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D037281:Calnexin