Trichomislin, a novel ribosome-inactivating protein, induces apoptosis that involves mitochondria and caspase-3.
Trichomislin, a novel ribosome-inactivating protein, was cloned from the genome of Trichosanthes kirilowii Maxim. The gene was recombined to prokaryotic expression vector and the protein was purified by cation-exchange chromatography. The secondary structure of trichomislin was measured by circular-dichroism analysis and the ratios of alpha-helices and beta-sheets were calculated. Trichomislin could inhibit the synthesis of protein in rabbit reticulocyte lysate systems and its reaction mechanism was to inactivate ribosome as an rRNA N-glycosidase. Antitumor analyses indicated trichomislin induced the apoptosis and inhibited the growth of choriocarcinoma cells. Further investigation showed that trichomislin could bind to and enter choriocarcinoma cells, and then increase the caspase-3 activity in a time-dependent manner. At the same time, the concentration of cytochrome c in cytosol increased while that in mitochondria decreased. These results suggested that trichomislin induced apoptosis by releasing cytochrome c from mitochondria which then triggered the caspase family member activation.
Mi
Shuang-Li
SL
The National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, China.
An
Cheng-Cai
CC
Wang
Ye
Y
Chen
Ji-Yuan
JY
Che
Nan-Ying
NY
Gao
Yin
Y
Chen
Zhang-Liang
ZL
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism / Q000502:physiology*; D002412:Cations; D045744:Cell Line, Tumor; D002852:Chromatography, Ion Exchange; D002942:Circular Dichroism; D003001:Cloning, Molecular; D045304:Cytochromes c / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D045647:DNA Glycosylases / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004926:Escherichia coli / Q000378:metabolism; D005822:Genetic Vectors; D006801:Humans; D008928:Mitochondria / Q000378:metabolism / Q000473:pathology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012335:RNA, Ribosomal / Q000737:chemistry; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D012156:Reticulocytes / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism / Q000473:pathology*; D013997:Time Factors
D002412:Cations; D012335:RNA, Ribosomal; D045304:Cytochromes c; D045647:DNA Glycosylases; C505407:CASP3 protein, human; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases