CFTR journey<< Back to Genetics and cell biology of CFTR
Click on the tabs to move through the sequence.
The entire process of CFTR protein synthesis can be broken down into five main steps:1-4
2. Translation and protein folding
3. Post-translational modification
4. Protein trafficking
5. Surface expression
Under normal circumstances the CFTR gene is tightly packed into a supercoil of DNA that forms the chromosome.
CFTR gene expression is initiated by cell signals (e.g. hormones) that instruct the chromosome to unravel and reveal the CFTR gene. A portable copy of the gene is made in the form of messenger RNA (mRNA) – this process is called transcription.
Ribosomes ‘read’ and translate the mRNA sequence into a polypeptide chain of amino acids (i.e. the immature CFTR protein). This is called translation. Upon reading the final three-letter signal or ‘STOP codon’, the ribosome releases the fully extended CFTR polypeptide, which ‘folds’ to form an immature CFTR channel.
After protein translation, the immature CFTR protein undergoes post-translational modification in Golgi bodies. During this process the unique 3-D structure of the CFTR protein continues to develop through a series of chemical modifications. This culminates with the channel being packaged in a vesicle for transport to the cell surface.
After post-translational modification, CFTR is packaged in vesicles for transport to the cell surface. This is called protein trafficking.
Finally, the vesicle carrying CFTR protein fuses with the membrane, allowing surface expression of CFTR. The CFTR can immediately begin functioning as an ion channel.