PMID- 10097113
OWN - NLM
STAT- MEDLINE
DCOM- 19990512
LR  - 20190501
IS  - 0027-8424 (Print)
IS  - 0027-8424 (Linking)
VI  - 96
IP  - 7
DP  - 1999 Mar 30
TI  - Deletion of the loop region of Bcl-2 completely blocks paclitaxel-induced
      apoptosis.
PG  - 3775-80
AB  - At high concentrations, the tubule poison paclitaxel is able to kill cancer cells
      that express Bcl-2; it inhibits the antiapoptotic activity of Bcl-2 by inducing
      its phosphorylation. To localize the site on Bcl-2 regulated by phosphorylation, 
      mutant forms of Bcl-2 were constructed. Mutant forms of Bcl-2 with an alteration 
      in serine at amino acid 70 (S70A) or with deletion of a 60-aa loop region between
      the alpha1 and alpha2 helices (Deltaloop Bcl-2, which also deletes amino acid 70)
      were unable to be phosphorylated by paclitaxel treatment of MDA-MB-231 cells into
      which the genes for the mutant proteins were transfected. The Deltaloop mutant
      completely inhibited paclitaxel-induced apoptosis. In cells expressing the S70A
      mutant, paclitaxel induced about one-third the level of apoptosis seen with
      wild-type Bcl-2. To evaluate the role of mitogen-activated protein kinases
      (MAPKs) in Bcl-2 phosphorylation, the activation of c-Jun N-terminal kinase
      (JNK), extracellular signal-regulated kinase (ERK), and p38 was examined.
      Paclitaxel-induced apoptosis was associated with phosphorylation of Bcl-2 and
      activation of ERK and JNK MAPKs. If JNK activation was blocked by transfections
      with either a stress-activated protein kinase kinase dominant-negative (K-->R)
      gene (which prevents the activation of a kinase upstream of JNK) or MAPK
      phosphatase-1 gene (which dephosphorylates and inactivates JNK), Bcl-2
      phosphorylation did not occur, and the cells were not killed by paclitaxel. By
      contrast, neither an ERK inhibitor (PD098059) nor p38 inhibitors (SB203580 and
      SB202190) had an effect on Bcl-2 phosphorylation. Thus, our data show that the
      antiapoptotic effects of Bcl-2 can be overcome by phosphorylation of Ser-70;
      forms of Bcl-2 lacking the loop region are much more effective at preventing
      apoptosis than wild-type Bcl-2 because they cannot be phosphorylated. JNK, but
      not ERK or p38 MAPK, appear to be involved in the phosphorylation of Bcl-2
      induced by paclitaxel.
FAU - Srivastava, R K
AU  - Srivastava RK
AD  - Laboratory of Immunology, National Institute on Aging, National Institutes of
      Health, 5600 Nathan Shock Drive, Baltimore, MD 21224-6825, USA.
FAU - Mi, Q S
AU  - Mi QS
FAU - Hardwick, J M
AU  - Hardwick JM
FAU - Longo, D L
AU  - Longo DL
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Proc Natl Acad Sci U S A
JT  - Proceedings of the National Academy of Sciences of the United States of America
JID - 7505876
RN  - 0 (Proto-Oncogene Proteins c-bcl-2)
RN  - 0 (Recombinant Proteins)
RN  - 452VLY9402 (Serine)
RN  - 5J49Q6B70F (Vincristine)
RN  - EC 2.7.11.17 (Calcium-Calmodulin-Dependent Protein Kinases)
RN  - EC 2.7.11.24 (JNK Mitogen-Activated Protein Kinases)
RN  - EC 2.7.11.24 (Mitogen-Activated Protein Kinases)
RN  - OF5P57N2ZX (Alanine)
RN  - P88XT4IS4D (Paclitaxel)
SB  - IM
MH  - Alanine
MH  - Amino Acid Substitution
MH  - Apoptosis/*drug effects/physiology
MH  - Breast Neoplasms
MH  - Calcium-Calmodulin-Dependent Protein Kinases/metabolism
MH  - Cytosol/metabolism
MH  - Female
MH  - Humans
MH  - JNK Mitogen-Activated Protein Kinases
MH  - Mitochondria/metabolism
MH  - *Mitogen-Activated Protein Kinases
MH  - Mutagenesis, Site-Directed
MH  - Paclitaxel/*toxicity
MH  - Phosphorylation
MH  - Point Mutation
MH  - Proto-Oncogene Proteins c-bcl-2/chemistry/*genetics/*metabolism
MH  - Recombinant Proteins/chemistry/metabolism
MH  - Sequence Deletion
MH  - Serine
MH  - Signal Transduction
MH  - Transfection
MH  - Tumor Cells, Cultured
MH  - Vincristine/toxicity
PMC - PMC22370
EDAT- 1999/03/31 00:00
MHDA- 1999/03/31 00:01
CRDT- 1999/03/31 00:00
PHST- 1999/03/31 00:00 [pubmed]
PHST- 1999/03/31 00:01 [medline]
PHST- 1999/03/31 00:00 [entrez]
AID - 10.1073/pnas.96.7.3775 [doi]
PST - ppublish
SO  - Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):3775-80. doi: 10.1073/pnas.96.7.3775.