What is the most likely fate of a protein with an Nterminal

What is the most likely fate of a protein with an N-terminal ER sorting signal and a hydrophobic domain of 22 amino acids? The protein stays in the cytosol The protein is transported to the mitochondrium because many transmembrane proteins function in ATP synthesis The protein is translocated all the way into the ER lumen The hydrophobic transmembrane domain is recognized once it is in the translocation channel and released sideways into the membrane The hydrophobic domain is cleaved off by signal peptidase

Solution

The protein is translocated all the way into the endoplasmic reticulum.

The endoplasmic reticulum is the first step in the \"secretory Pathway\" and follows an intersting phenomenon called the \"Co translational Translocation\". Th eribosome forms an ribosome mRNA SRP complex and binds to a receptor on the surface of RER when the protein synthesis resume and proteins are cotranslationally extruded through the membrane of ER into the lumen of ER where the hydrophobic signal sequence is cleaved off by signal peptides.