Within the nucleus, R-Smads are modified by:

Phosphorylation of linker domains

Acetylation of MH1 domains

Dephosphorylation of the C-terminal serines by nuclear

phosphatases

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CFTR protein contains

a di-acidic sorting signal that binds to the Sec24 subunit

of the COPII vesicle coat and is necessary for transport of

the CFTR protein out of the ER.

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Most common CFTR mutation is a ΔF508 -

Prevents normal transport of CFTR to the plasma membrane by blocking its packaging into COPII vesicles budding from the ER. 

Change the conformation of the cytosolic portion of CFTR so that the signal is unable to bind to Sec24.

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Rab GTPases 

associate with transport vesicles and act as key regulators of vesicle trafficking to and fusion with the appropriate target membrane.

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Rab·GTP is enabled to bind to a variety of different proteins, known as Rab effectors.

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In yeast Rab protein is the Sec4 and its effectors are exocyst and Type V Myosin.

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In mammalian cells, Rab5 protein (early endosomes) and its effector protein known as EEA1 (early endosome antigen 1)