Protein Domain : Protein import receptor MAS20, metazoan IPR022422

Type	Family
Description	Virtually all mitochondrial precursors are imported via the same mechanism [ ]: precursors first bind to receptors on the mitochondrial surface, then insert into the translocation channel in the outer membrane. Many outer-membrane proteins participate in the early stages of import, 4 of which (MAS20, MAS22, MAS37 and MAS70) are components of the receptor. MAS20, which forms a subcomplex with MAS22, seems to interact with most or all mitochondrial precursors, suggesting that the protein binds directly to mitochondrial targeting sequences. The MAS37 and MAS70 components also form a subcomplex, the 2 subcomplexes possibly binding via their trans-membrane (TM) regions -the TM region of MAS70 promotes oligomerisation of attatched protein domains and shares sequence similarity with the TM region of MAS20 []. The human homologue of the fungal MAS20 (TOM20) import receptor has been identified and characterised [ ]. Although the amino acid sequences exhibit pronounced differences, similarity is greatest in the N-terminal third of the molecules. The structure of the rat TOM20 import receptor has been determined by NMR []. The cytosolic domain forms an all-alpha structure, with a hydrophobic groove that mediates presequence binding [].
Short Name	MAS20_rcpt_metazoan