which cellular compartments would be directly be affected by a defect in protein trafficking in the er? Why?
The endoplasmic reticulum serves many general functions, including the folding of protein molecules in sacs called cisternae and the transport of synthesized proteins in vesicles to the Golgi apparatus. Secretory proteins, mostly glycoproteins, are moved across the endoplasmic reticulum membrane. Proteins that are transported by the endoplasmic reticulum throughout the cell are marked with an address tag called a signal sequence. First of all would suffer plasmalemma and membranes of all compartments because ER transports proteins to them. In that case all the transportation processes would be disrupted.Also such structural proteins like vimentin or keratines shoud be transported to the Golgi apparatus by ER. Their absence would cause the great problems in the cytoskeleton functioning. And it is likely that the whole cell would be destroyed within a few minutes.