Caspase 3 activation is controlled by a sequence located in the N-terminus of its large subunit.
We report that the induction and completion of the apoptotic program is delayed in a doxorubicin-resistant cell line (HL60/ADR). This hindrance to cell death occurred downstream of the multidrug-resistant protein (mrp), a transmembrane transporter. In vitro studies showed that these cells were incapable of correctly activating procaspase 3 (pC3), the main executioner of apoptosis. Sequencing of HL60/ADR pC3 revealed point mutations in a sequence located in the N-terminal region of the large subunit of caspase 3 (C3, amino acids 31-37; i.e., immediately after the propeptide). We called this particular form of C3, the C3 N-terminal modified (C3-NTM), and show that it is partially active when transfected into MCF-7 cells shown to have little or no endogenous pC3. As a deletion of the amino acids 31-37 in wild-type C3 leads to the same phenotype, we conclude that this sequence is involved in C3 activation during apoptosis.
Pelletier
Maude
M
IFR 26, INSERM U601, 9 quai Moncousu, 44035 Nantes Cedex 01, France.
Cartron
Pierre-François
PF
Delaval
Floriane
F
Meflah
Khaled
K
Vallette
François M
FM
Oliver
Lisa
L
D000595:Amino Acid Sequence; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004351:Drug Resistance; D004789:Enzyme Activation; D018922:HL-60 Cells; D006801:Humans; D008969:Molecular Sequence Data; D017354:Point Mutation; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment
D021122:Protein Subunits; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases