Question

Which of the following proteins or protein complexes is directly required for the targeting of mitochondrial inner membrane multipass proteins, such as metabolite transporters, whose signal sequence is normally not cleaved after import?

A. TIM22
B. TIM23
C. OXA
D. Mia40
E. SAM

Answer 1

TIM22 is the protein complex required for targeting multipass proteins to the mitochondrial inner membrane, where these proteins are inserted into the membrane.

Step-by-step explanation:

The protein complex directly required for the targeting of mitochondrial inner membrane multipass proteins, such as metabolite transporters, whose signal sequence is normally not cleaved after import, is protein complex TIM22. The TIM22 complex is responsible for the insertion of polytopic proteins into the inner mitochondrial membrane. These proteins, which contain multiple transmembrane segments, are recognized by their internal targeting sequences and are inserted into the membrane in a stepwise manner, facilitated by TIM22.