Type I Membrane Proteins Have All of the Following Properties,except

Question

Type I membrane proteins have all of the following properties,except:
A)cleavable signal sequence.
B)internal signal-anchor sequence.
C)internal stop-transfer sequence.
D)N-out,C-in topology.

Accepted Answer

Type I membrane proteins typically have a cleavable signal sequence that targets the protein to the endoplasmic reticulum membrane, an N-out,C-in topology meaning the N-terminus is outside the cell or organelle and the C-terminus is inside, and they may have a stop-transfer sequence that halts translocation across the membrane, anchoring the protein in the membrane. However, they do not characteristically have an internal signal-anchor sequence; this feature is more typical of Type II and Type III membrane proteins, which use such sequences both to target to the membrane and to anchor themselves within it.