1.)The mitochondrial membrane proteins ,β-barrel proteins, are found in the outer membrane,

2.)They function in the biogenesis of mitochondria.

3.)Structures determined for  β-barrel proteins  show that  these proteins have barrel structures formed by anti-parallel β-strands embedded in the lipid bilayer.

4.)They  form functional complexes with other outer membrane protein.

5.)The sorting and assembly machinery (SAM) complex functions in the assembly of β-barrel proteins into the mitochondrial outer membrane.

6.)It is related to the Omp85/YaeT machinery in bacterial outer membranes.

7.)The eukaryotic SAM complex is distinguished by two peripheral subunits, Sam37 and Sam35.

8.)Sam35 is required for the SAM complex to bind outer membrane substrate proteins: 9.)Destabilization of Sam35 inhibits substrate binding by Sam50. Sam37 acts later than Sam35, apparently to assist release of substrates from the SAM complex 

10.)Sam50, the membrane-embedded subunit of the SAM complex, is an essential protein predicted to have a β-barrel topology,

Thus the  complex formed between Sam50, Sam35, and Sam37 is responsible for the assembly of all β-barrel proteins in yeast, and it is known  as the SAM complex.