Mutations in the passenger polypeptide can affect its partitioning between mitochondria and cytoplasm: mutations can impair the mitochondrial import of DsRed.
In this study, we report that the partitioning between mitochondria and cytoplasm of two variants, mCherry and DsRed Express (DRE), of the red fluorescent protein, DsRed, fused to one of the six matrix targeting sequences (MTSs) can be affected by both MTS and amino acid substitutions in DsRed. Of the six MTSs tested, MTSs from superoxide dismutase and DNA polymerase gamma failed to direct mCherry, but not DRE to mitochondria. By evaluating a series of chimeras between mCherry and DRE fused to the MTS of superoxide dismutase, we attribute the differences in the mitochondrial partitioning to differences in the primary amino acid sequence of the passenger polypeptide. The impairment of mitochondrial partitioning closely parallels the number of mCherry-specific mutations, and is not specific to mutations located in any particular region of the polypeptide. These observations suggest that both MTS and the passenger polypeptide affect the efficiency of mitochondrial import and provide a rationale for the observed diversity in the primary amino acid sequences of natural MTSs.
Pastukh
Viktoriya
V
Department of Cell Biology and Neuroscience, University of South Alabama, 307 University Blvd., MSB1201, Mobile, AL 36688, USA.
Shokolenko
Inna N
IN
Wilson
Glenn L
GL
Alexeyev
Mikhail F
MF
D000595:Amino Acid Sequence; D006367:HeLa Cells; D006801:Humans; D008164:Luminescent Proteins / Q000737:chemistry / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D010455:Peptides / Q000235:genetics*; D021382:Protein Sorting Signals; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015203:Reproducibility of Results; D016415:Sequence Alignment; D013347:Subcellular Fractions / Q000378:metabolism; D000097573:Red Fluorescent Protein
D008164:Luminescent Proteins; D010455:Peptides; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; D000097573:Red Fluorescent Protein; C413663:fluorescent protein 583