Polypyrimidine tract-binding proteins are cleaved by caspase-3 during apoptosis
SCIE
SCOPUS
- Title
- Polypyrimidine tract-binding proteins are cleaved by caspase-3 during apoptosis
- Authors
- Back, SH; Shin, SJ; Jang, SK
- Date Issued
- 2002-07-26
- Publisher
- AMER SOC BIOCHEMISTRY MOLECULAR BIOLO
- Abstract
- The polypyrimidine tract-binding protein (PTB), an RNA-binding protein, is required for efficient translation of some mRNAs containing internal ribosomal entry sites (IRESs). Here we provide evidence that the addition of apoptosis-inducing agents to cells results in the cleavage of PTB isoforms 1, 2, and 4 by caspase-3. This cleavage of PTB separated the N-terminal region, containing NLS-RRM1, from the C-terminal region, containing RRM2-3-4. Our data indicate that there are three noncanonical caspase-3 target sites in PTBs, namely Ile-Val-Pro-Asp(7) down arrow Ile, Leu-Tyr-Thr-Asp(139) down arrow Ser, and Ala-Ala-Val-Asp(172) down arrow Ala. The C-terminal PTB fragments localized to the cytoplasm, as opposed to the nucleus where most intact PTBs are found. Moreover, these G terminal PTB fragments inhibited translation of polio-viral mRNA, which contains an IRES element requiring PTB for its activation. This suggests that translation of some IRES-containing mRNAs is regulated by proteolytic cleavage of PTB during apoptosis.
- Keywords
- RIBOSOME-ENTRY-SITE; INITIATION-FACTOR 4G; MOUTH-DISEASE VIRUS; CAP-INDEPENDENT TRANSLATION; 5' NONTRANSLATED REGION; PROGRAMMED CELL-DEATH; MESSENGER-RNA; INTERNAL INITIATION; FUNCTIONAL REQUIREMENT; MEDIATED TRANSLATION
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/18970
- DOI
- 10.1074/jbc.M203887200
- ISSN
- 0021-9258
- Article Type
- Article
- Citation
- JOURNAL OF BIOLOGICAL CHEMISTRY, vol. 277, no. 30, page. 27200 - 27209, 2002-07-26
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