A short C-terminal tail prevents mis-targeting of hydrophobic mitochondrial membrane proteins to the ER.
Sdh3/Shh3, a subunit of mitochondrial succinate dehydrogenase, contains transmembrane domains with a hydrophobicity comparable to that of endoplasmic reticulum (ER) proteins. Here, we show that a C-terminal reporter fusion to Sdh3/Shh3 results in partial mis-targeting of the protein to the ER. This mis-targeting is mediated by the signal recognition particle (SRP) and depends on the length of the C-terminal tail. These results imply that if nuclear-encoded mitochondrial proteins contain strongly hydrophobic transmembrane domains and a long C-terminal tail, they have the potential to be recognized by SRP and mis-targeted to the ER.
School of Biological Sciences, Seoul National University, Seoul 151-747, South Korea; Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
Johannes H
JH
Reithinger
Chewon
C
Yim
Kwangjin
K
Park
Patrik
P
Björkholm
Gunnar
G
von Heijne
Hyun
H
Kim
D000595:Amino Acid Sequence; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D050576:Membrane Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000737:chemistry / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000378:metabolism*; D008969:Molecular Sequence Data; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D018271:Signal Recognition Particle / Q000378:metabolism; D013385:Succinate Dehydrogenase / Q000737:chemistry / Q000378:metabolism*
D050576:Membrane Fusion Proteins; D033681:Mitochondrial Membrane Transport Proteins; D018271:Signal Recognition Particle; D013385:Succinate Dehydrogenase
Co-translational translocation; Endoplasmic reticulum; Mitochondria; Signal sequence; Succinate dehydrogenase