The function and specificity of the C-terminal tripeptide glyoxysomal targeting signal in Neurospora crassa.
The function of the C-terminal tripeptide targeting signal responsible for microbody targeting in many eukaryotes has been investigated in the filamentous fungus Neurospora crassa. Using an in-vivo targeting assay that employs transformants carrying C-terminally-modified versions of the bacterial enzyme chloramphenicol acetyltransferase (CAT), it has been demonstrated that C-terminal tripeptide-dependent import occurs most efficiently in response to nutritional acetate-induction. Under these conditions Neurospora generates a specialized organelle, the glyoxysome, which carries the enzymes responsible for the glyoxylate cycle and can be distinguished from peroxisome-like microbodies that contain catalase. Moreover, several C-terminal peptides have been tested in this system to extend the tripeptide targeting consensus to A/C/G/S-H/K/Q/R-I/L/V. However, the tripeptide analogue, ARM, found at the C-terminus of the glyoxylate cycle enzyme isocitrate lyase in higher plants, does not apparently function here.
de Zoysa
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PA
Department of Microbiology, University of Reading, Whiteknights, UK.
Connerton
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IF
D000595:Amino Acid Sequence; D001483:Base Sequence; D015139:Blotting, Southern; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D003001:Cloning, Molecular; D016384:Consensus Sequence; D004271:DNA, Fungal / Q000378:metabolism; D006038:Glyoxylates / Q000378:metabolism; D007522:Isocitrate Lyase / Q000096:biosynthesis*; D008830:Microbodies / Q000378:metabolism*; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides; D021382:Protein Sorting Signals / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D013379:Substrate Specificity
D004271:DNA, Fungal; D006038:Glyoxylates; D009838:Oligodeoxyribonucleotides; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D015500:Chloramphenicol O-Acetyltransferase; D007522:Isocitrate Lyase