Isolation of a cDNA clone specifying rat chaperonin 10, a stress-inducible mitochondrial matrix protein synthesised without a cleavable presequence.
We have isolated a cDNA clone encoding chaperonin 10 from rat liver. The cDNA specifies a protein of 102 amino acids which, when transcribed and translated in vitro, yields a single basic product (pI > 9) that co-migrates exactly with the heat shock inducible cpn10 of rat hepatoma cells during 2D gel-electrophoresis. It is concluded that cpn10, unlike the majority of nuclear-encoded proteins of the mitochondrial matrix, is synthesised without a cleavable targeting signal and that, following removal of the initiating methionine, it becomes acetylated prior to mitochondrial import. Incubation of 3H- or 35S-labelled cpn10 with mitochondria confirms these conclusions and shows that cpn10 is imported into mitochondria in an energy-dependent process which is inhibited by the presence of 2,4-dinitrophenol.
Ryan
M T
MT
Department of Biochemistry, La Trobe University, Bundoora, Vic., Australia.
Hoogenraad
N J
NJ
Høj
P B
PB
D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000378:metabolism; D001426:Bacterial Proteins / Q000096:biosynthesis; D001483:Base Sequence; D002417:Cattle; D018835:Chaperonin 10; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary / Q000302:isolation & purification*; D015723:Gene Library; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism; D008114:Liver Neoplasms, Experimental / Q000378:metabolism; D008930:Mitochondria, Liver / Q000378:metabolism*; D008969:Molecular Sequence Data; D010944:Plants / Q000378:metabolism; D012333:RNA, Messenger / Q000302:isolation & purification / Q000378:metabolism; D051381:Rats; D017386:Sequence Homology, Amino Acid; D014407:Tumor Cells, Cultured
D001426:Bacterial Proteins; D018835:Chaperonin 10; D017931:DNA Primers; D018076:DNA, Complementary; D006360:Heat-Shock Proteins; D012333:RNA, Messenger