• Animal cells and systems
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• v.8 no.3
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• pp.205-212
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• 2004

The tumor suppressor protein p53 is stabilized by the herpes-virus-associated ubiquitin-specific protease (HAUSP), a deubiquitinating enzyme. We previously isolated and characterized a mouse orthologue of HAUSP, mHAUSP. mHAUSP cDNA consisted of 3,312 bp encodes 1,103 amino acids with a molecular weight of approximately 135 kDa containing highly conserved Cys, Asp (I), His, and Asn/Asp (II) domains. In this study, we carried out site-directed mutagenesis of 6 conserved amino acids (Cys224, Gln231, Asp296, His457, His465, and Asp482) in Cys box, QQD box, and His box. Interestingly, the conserved Gln 231 was not essential for the catalytic activity of mHAUSP. However, the other conserved amino acids were required for deubiquitinating activity of mHAUSP. We performed isopeptidase assay and confirmed that mHAUSP is able to remove ubiquitin from ubiquitinated substrates. In addition, we observed that mHAUSP induces apoptosis in HeLa cells.

• Proceedings of the Zoological Society Korea Conference
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• 2001.10a
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• pp.202.2-202
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• 2001

No Abstract, See Full Text

• BMB Reports
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• v.46 no.12
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• pp.588-593
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• 2013

Apoptosis, programmed cell death, is a process involved in the development and maintenance of cell homeostasis in multicellular organisms. It is typically accompanied by the activation of a class of cysteine proteases called caspases. Apoptotic caspases are classified into the initiator caspases and the executioner caspases, according to the stage of their action in apoptotic processes. Although caspase-3, a typical executioner caspase, has been studied for its mechanism and substrates, little is known of caspase-6, one of the executioner caspases. To understand the biological functions of caspase-6, we performed proteomics analyses, to seek for novel caspase-6 substrates, using recombinant caspase-6 and HepG2 extract. Consequently, 34 different candidate proteins were identified, through 2-dimensional electrophoresis/MALDI-TOF analyses. Of these identified proteins, 8 proteins were validated with in vitro and in vivo cleavage assay. Herein, we report that HAUSP, Kinesin5B, GEP100, SDCCAG3 and PARD3 are novel substrates for caspase-6 during apoptosis.