Integral Membrane Proteins

In type 1, where is N terminus

Lumen, cut off with signal sequence

In type 1, where is C terminus

Cytosol

In type 2, where is N terminus

Cytosol

In type 2, where is C terminus

Lumen

Type 3 N terminus is…

Very short, in lumen

Type 3 C terminus is in…

Cytosol

Type 4a N terminus is…

In cytosol

Type 4b, N terminus is in…

Lumen

Type 4a, C terminus is in…

Cytosol

Type 4b, C terminus is in…

Cytosol

In the absence of a signal sequence, what signals ribosome to bind ER

Internal hydrophobic signal anchor sequence

Tail anchored proteins have no…

N terminal signal sequence

Tail anchored proteins have a hydrophobic…

C terminus

GPI anchored proteins structure

Covalently attached protein in membrane

In GPI anchored proteins, C terminus is …

covalently attached to membrane

In GPI anchored proteins, N terminus is in…

ER lumen

Orientation of N and C in type 2

N in cytosol, C in ER lumen

Orientation of type 3 N and C

N in ER lumen, C in cytosol

Step 1 of tail anchored protein membrane insertion

Sgt2, get4,and get5 sequesters nascent protein hydrophobic c terminus tail anchor sequence and transfers it to get3-atp

Step 2 of tail anchored proteins membrane insertion

Get3-atp-nascent protein complex docks onto er membrane dimeric get1/get2 receptor

Step 3 of tail anchored proteins membrane insertion

Get3 atp hydrolysis and release of tail anchored proteins into the get1/get2 receptor, which releases it into er membrane

Step 4 of tail anchored protein membrane insertion

Get3 release of ADP and binding of atp releases it from get1/get2