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Covalent modification of proteins by a small peptide Zfra
Author(s) -
Chang NanShan,
Lee MingHui,
Lin SingRu
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.838.2
Subject(s) - wwox , peptide , ubiquitin , cytosol , chemistry , enzyme , proteasome , apoptosis , in vivo , cytochrome c , microbiology and biotechnology , suppressor , biochemistry , cancer cell , biology , cancer , genetics , gene
Post‐translational modification of proteins is crucial for protein functional maturation and/or degradation. We have previously isolated a 3.5‐kDa protein Zfra. Zfra blocks the function of tumor suppressors WWOX and p53 and inhibit cytochrome c release during the mitochondrial pathway of apoptosis. Notably, upon exposure to phosphate under cell‐ and enzyme‐free conditions, Zfra undergoes a rapid self‐polymerization for more than 50 fold (>200 kDa). When cytosolic proteins undergo “zfration”, the zfrated proteins tend to degrade independently of the ubiquitination/proteasome system. Intratumor injection of a Zfra peptide enhances the growth of skin basal cell carcinoma and breast and prostate cancer cells in nude mice by 3–4 fold in 3 months, suggestive of its inactivation of tumor suppressors (e.g. p53 and WWOX) in vivo. Together, Zfra is a universal modifier of many proteins, and the modification probably occurs independently of enzymes. [supported by NSC and NHRI, Taiwan, and DoD, USA]