The cytosolic DnaJ-like protein djp1p is involved specifically in peroxisomal protein import.
The Saccharomyces cerevisiae DJP1 gene encodes a cytosolic protein homologous to Escherichia coli DnaJ. DnaJ homologues act in conjunction with molecular chaperones of the Hsp70 protein family in a variety of cellular processes. Cells with a DJP1 gene deletion are viable and exhibit a novel phenotype among cytosolic J-protein mutants in that they have a specific impairment of only one organelle, the peroxisome. The phenotype was also unique among peroxisome assembly mutants: peroxisomal matrix proteins were mislocalized to the cytoplasm to a varying extent, and peroxisomal structures failed to grow to full size and exhibited a broad range of buoyant densities. Import of marker proteins for the endoplasmic reticulum, nucleus, and mitochondria was normal. Furthermore, the metabolic adaptation to a change in carbon source, a complex multistep process, was unaffected in a DJP1 gene deletion mutant. We conclude that Djp1p is specifically required for peroxisomal protein import.
Department of Biochemistry, Academic Medical Center, 1105 AZ Amsterdam, The Netherlands.
E H
EH
Hettema
C C
CC
Ruigrok
M G
MG
Koerkamp
M
M
van den Berg
H F
HF
Tabak
B
B
Distel
I
I
Braakman
D000595:Amino Acid Sequence; D001483:Base Sequence; D001693:Biological Transport, Active; D003001:Cloning, Molecular; D003600:Cytosol / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015870:Gene Expression; D005800:Genes, Fungal; D049452:Green Fluorescent Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008830:Microbodies / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; C494635:DnaJ protein, E coli; D029968:Escherichia coli Proteins; D005656:Fungal Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins