Understanding the function–structure and function–mutation relationships of p53 tumor suppressor protein by high-resolution missense mutation analysis

Abstract

Inactivation of the tumor suppressor p53 by missense mutations is the most frequent genetic alteration in human cancers. The common missense mutations in the TP53 gene disrupt the ability of p53 to bind to DNA and consequently to transactivate downstream genes. However, it is still not fully understood how a large number of the remaining mutations affect p53 structure and function. Here, we used a comprehensive site-directed mutagenesis technique and a yeastbased functional assay to construct, express, and evaluate 2,314 p53 mutants representing all possible amino acid substitutions caused by a point mutation throughout the protein (5.9 substitutions per residue), and correlated p53 function with structure-and tumor-derived mutations. This high-resolution mutation analysis allows evaluation of previous predictions and hypotheses through interrelation of function, structure and mutation.

p53 and disease: when the guardian angel fails

“…54,55,56 The in vitro functional studies mentioned earlier 57 lend support to the contention that different p53 mutations may be associated with different phenotypic properties, including tumor aggressiveness. However, another possibility is that any observed differences in patient A summary of the data from the studies discussed in this review is given.…”

“…Clearly, there could be major advantages in screening for p53 mutation prior to randomization in future clinical trials, particularly in light of increased knowledge on the functional activities of different mutations. 47,57 TP53 mutations are reported to predict resistance to anthracycline, 54 doxorubicin 59 and 5-fluorouracil/mitomycin 60 in breast cancer. Mutations affecting the L2 and L3 loop structures in particular were associated with lack of response to chemotherapy.…”

Mutant p53 subverts p63 control over KLF4 expression in keratinocytes

“…For knockdown experiments, 50 nM siRNA oligonucleotides, with a scrambled sequence (Ambion, Foster City, CA, USA), or targeting the central DNA-binding domain of p63 or against p53 (5 0 -GACUCCAGUGGUAAUCUACTT-3 0 ), were used. For overexpression experiments, we used pcDNA3 vector, pcDNA3-DNp63a, pcDNA3-p53 wild type, pCR259-p53R282Q and pCR259-p53H179Y (Kato et al, 2003). The KLF4 promoter-LUC was kindly provided by Vincent W Yang (Emory University, Atlanta, GA, USA).…”

Transcription regulation by mutant p53

“…This results in conformational alteration of the DBD, typically leading to loss of the most prominent biochemical activity of wtp53, namely its ability to trigger sequence-specific transcriptional activation, which underlies much of wild-type p53's tumor suppressor functions. Different p53 mutants can display different degrees of impairment of their transactivation potential, reflecting the nonidentical impact of individual mutations on the overall structure of the mutant protein (Pan and Haines, 2000;Inga et al, 2002;Kato et al, 2003). Retention of residual SSDB capacity in a particular p53 mutant might result in p53-RE-dependent activation of some promoters but not others.…”