Defective folding of mutant p16(INK4) proteins encoded by tumor-derived alleles

被引:59
作者
Zhang, B [1 ]
Peng, ZY [1 ]
机构
[1] UNIV CONNECTICUT,CTR HLTH,DEPT BIOCHEM,FARMINGTON,CT 06032
关键词
D O I
10.1074/jbc.271.46.28734
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
p16(INK4) is a specific cyclin D-dependent kinase inhibitor and a multiple tumor suppressor. Inactivation of p16 is frequent in both primary tumors and tumor-derived cell lines. We describe here the conformational properties and oligomerization state of seven mutant p16 proteins; all of them are deficient in function. Four of the seven proteins show significantly disrupted secondary structure and backbone folding. The other three adopt partially folded, molten globule-like conformations. These proteins have near-native levels of secondary structure, but lack the ability to undergo a cooperative thermal transition and are substantially less resistant to proteolysis than is wild type p16. At low concentrations, two of the seven proteins are monomers, three exhibit an apparent molecular weight between the value of a monomer and a dimer, and the other two aggregate significantly. Our results strongly suggest that defective protein folding and/or aggregation is a common mechanism for inactivation of p16.
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页码:28734 / 28737
页数:4
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