[Role of Bid protein in the mitochondria and Endoplasmic Reticulum associated apoptotic pathway].
OBJECTIVE
To explore the role of Bid protein in the mitochondria and endoplasmic reticulum (ER) associated apoptotic pathway.


METHODS
Apoptosis of MUTZ-1 cells induced by homoharringtonine (HHT) was measured by FACS. Mitochondria and ER associated apoptotic pathway was detected by RT-PCR and Western blotting. And the translocation of Bid protein was measured by laser scanning confocal microscope (LSCM).


RESULTS
After exposure of MUTZ-1 to HHT at 0.05 microg/ml for 24 h, typical ER-stress phenomenon induced apoptotic cells and release of Ca2+ from the cytosolic Ca2+ storage and the loss of mitochondrial membrane potential were observed. RT-PCR analysis revealed that mRNAs for ER stress-associated proapoptotic factor were markedly increased at 4 h after 0.05 microg/ml HHT treatment and peaked at 12 h, then decreased steady. Activation of caspase protein was also observed at 8 h. The translocation of Bid protein from ER to mitochondria was observed at 12 h after HHT treatment.


CONCLUSIONS
HHT can induce MUTZ-1 cells apoptosis. The cell death may be likely mediated by the ER stress pathway as well as mitochondrial pathway and Bid protein may be the cross talk of the two apoptotic pathways.
Hu
Jie
J
Department of Hematology, First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou 310003, China.
He
Dong-Hua
DH
Gao
Liang
L
Yang
Chun-Hu
CH
Cai
Zhen
Z
D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D051023:BH3 Interacting Domain Death Agonist Protein / Q000378:metabolism / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D053471:Caspases, Initiator / Q000378:metabolism; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000502:physiology*; D006248:Harringtonines / Q000494:pharmacology; D000077863:Homoharringtonine; D006801:Humans; D008928:Mitochondria / Q000378:metabolism / Q000502:physiology*; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors / Q000378:metabolism
D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D004268:DNA-Binding Proteins; D006248:Harringtonines; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors; D000077863:Homoharringtonine; C093516:CASP4 protein, human; D053148:Caspase 3; D053471:Caspases, Initiator; D002118:Calcium