The protein import receptor MOM19 of yeast mitochondria

[摘要]

We have identified the protein import receptor MOM19 of Saccharomyces cerevisiae mitochondria. MOM19 is exposed on the outer membrane surface and present in the mitochondrial receptor complex. Antibodies raised against MOM19 strongly inhibited the import of preproteins into isolated yeast mitochondria. Fab fragments prepared from the antibodies showed the same inhibitory effect. By using mutant mitochondria, which lacked the second import receptor MOM72, we found that the import of preproteins via MOM19 did not require the presence of MOM72. We conclude that MOM19 is required for preprotein translocation across the yeast mitochondrial outer membrane and is able to function independently of the receptor MOM72.

[学科分类] 生物化学/生物物理

[关键词] Mitochondrion;Receptor;MOM19;Preprotein;Protein translocation;AAC;ADP/ATP carrier;α-MPP;α-subunit of the matrix processing peptidase;F1β;β-subunit of the F1-ATPase;GIP;general insertion pore;MOM19;MOM72;mitochondrial outer membrane proteins (import receptors) of about 19 kDa and 72 kDa;respectively;MOM38;mitochondrial outer membrane protein of about 38 kDa (component of GIP);identical to ISP42 (import site protein of about 42 kDa);Su9-DHFR;fusion protein between the presequence of F0-ATPase subunit 9 and dihydrofolate reductase