The mannose 6-phosphate (M6P) receptors are crucial for delivering lysosomal proteins to lysosomes, while the KDEL recep

[answerhappygod]

The mannose 6-phosphate (M6P) receptors are crucial for delivering lysosomal proteins to lysosomes, while the KDEL receptors are important to send the ER resident proteins back to the ER. Which of the following statements is INCORRECT regarding the M6P receptors and the KDEL receptors?
They both shuttle back and forth between different membrane-enclosed compartments.
They are both transmembrane proteins.
They both release their soluble binding targets at a lower pH.
They both prevent the escape of proteins to the cell exterior by the “default” pathway.