scholarly journals The oncogenicity of tumor-derived mutant p53 is enhanced by the recruitment of PLK3

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Catherine A. Vaughan ◽  
Shilpa Singh ◽  
Mark A. Subler ◽  
Jolene J. Windle ◽  
Kazushi Inoue ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Amino Acid ◽  
Mouse Model ◽  
Single Amino Acid ◽  
Mutant P53 ◽  
Transactivation Domain ◽  
P53 Mutations ◽  
Gain Of Function ◽  
Transactivation Activity ◽  
Club Cells

Abstractp53 mutations with single amino acid changes in cancer often lead to dominant oncogenic changes. Here, we have developed a mouse model of gain-of-function (GOF) p53-driven lung cancer utilizing conditionally active LSL p53-R172H and LSL K-Ras-G12D knock-in alleles that can be activated by Cre in lung club cells. Mutation of the p53 transactivation domain (TAD) (p53-L25Q/W26S/R172H) eliminating significant transactivation activity resulted in loss of tumorigenicity, demonstrating that transactivation mediated by or dependent on TAD is required for oncogenicity by GOF p53. GOF p53 TAD mutations significantly reduce phosphorylation of nearby p53 serine 20 (S20), which is a target for PLK3 phosphorylation. Knocking out PLK3 attenuated S20 phosphorylation along with transactivation and oncogenicity by GOF p53, indicating that GOF p53 exploits PLK3 to trigger its transactivation capability and exert oncogenic functions. Our data show a mechanistic involvement of PLK3 in mutant p53 pathway of oncogenesis.

scholarly journals The lung-enriched p53 mutants V157F and R158L/P regulate a gain of function transcriptome in lung cancer

2019 ◽  
Vol 41 (1) ◽  
pp. 67-77 ◽  
Author(s):  
Julie A Barta ◽  
Kristen Pauley ◽  
Andrew V Kossenkov ◽  
Steven B McMahon
Keyword(s):  
Lung Cancer ◽  
Tumor Suppressor ◽  
Target Genes ◽  
Human Lung ◽  
De Novo ◽  
Human Lung Cancer ◽  
Migration And Invasion ◽  
Mutant P53 ◽  
P53 Mutations ◽  
Gain Of Function

Abstract Lung cancer is the leading cause of cancer-related deaths in the USA, and alterations in the tumor suppressor gene TP53 are the most frequent somatic mutation among all histologic subtypes of lung cancer. Mutations in TP53 frequently result in a protein that exhibits not only loss of tumor suppressor capability but also oncogenic gain-of-function (GOF). The canonical p53 hotspot mutants R175H and R273H, for example, confer upon tumors a metastatic phenotype in murine models of mutant p53. To the best of our knowledge, GOF phenotypes of the less often studied V157, R158 and A159 mutants—which occur with higher frequency in lung cancer compared with other solid tumors—have not been defined. In this study, we aimed to define whether the lung mutants are simply equivalent to full loss of the p53 locus, or whether they additionally acquire the ability to drive new downstream effector pathways. Using a publicly available human lung cancer dataset, we characterized patients with V157, R158 and A159 p53 mutations. In addition, we show here that cell lines with mutant p53-V157F, p53-R158L and p53-R158P exhibit a loss of expression of canonical wild-type p53 target genes. Furthermore, these lung-enriched p53 mutants regulate genes not previously linked to p53 function including PLAU. Paradoxically, mutant p53 represses genes associated with increased cell viability, migration and invasion. These findings collectively represent the first demonstration that lung-enriched p53 mutations at V157 and R158 regulate a novel transcriptome in human lung cancer cells and may confer de novo function.

scholarly journals Gain-of-Function Mutations inUPC2Are a Frequent Cause ofERG11Upregulation in Azole-Resistant Clinical Isolates of Candida albicans

2012 ◽  
Vol 11 (10) ◽  
pp. 1289-1299 ◽  
Author(s):  
Stephanie A. Flowers ◽  
Katherine S. Barker ◽  
Elizabeth L. Berkow ◽  
Geoffrey Toner ◽  
Sean G. Chadwick ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Amino Acid ◽  
Clinical Isolates ◽  
Transcriptional Analysis ◽  
Single Amino Acid ◽  
Ergosterol Biosynthesis ◽  
Amino Acid Substitutions ◽  
Gain Of Function ◽  
Content Type ◽  
Zinc Cluster

ABSTRACTInCandida albicans, Upc2 is a zinc-cluster transcription factor that targets genes, including those of the ergosterol biosynthesis pathway. To date, three documentedUPC2gain-of-function (GOF) mutations have been recovered from fluconazole-resistant clinical isolates that contribute to an increase inERG11expression and decreased fluconazole susceptibility. In a group of 63 isolates with reduced susceptibility to fluconazole, we found that 47 overexpressedERG11by at least 2-fold over the average expression levels in 3 unrelated fluconazole-susceptible strains. Of those 47 isolates, 29 contained a mutation inUPC2, whereas the remaining 18 isolates did not. Among the isolates containing mutations inUPC2, we recovered eight distinct mutations resulting in putative single amino acid substitutions: G648D, G648S, A643T, A643V, Y642F, G304R, A646V, and W478C. Seven of these resulted in increasedERG11expression, increased cellular ergosterol, and decreased susceptibility to fluconazole compared to the results for the wild-type strain. Genome-wide transcriptional analysis was performed for the four strongest Upc2 amino acid substitutions (A643V, G648D, G648S, and Y642F). Genes commonly upregulated by all four mutations included those involved in ergosterol biosynthesis, in oxidoreductase activity, the major facilitator efflux pump encoded by theMDR1gene, and the uncharacterized ATP binding cassette transporterCDR11. These findings demonstrate that gain-of-function mutations inUPC2are more prevalent among clinical isolates than previously thought and make a significant contribution to azole antifungal resistance, but the findings do not account forERG11overexpression in all such isolates ofC. albicans.

scholarly journals Role of hydrophobic amino acid clusters in the transactivation activity of the human glucocorticoid receptor.

1997 ◽  
Vol 17 (2) ◽  
pp. 934-945 ◽  
Author(s):  
T Almlöf ◽  
J A Gustafsson ◽  
A P Wright
Keyword(s):  
Amino Acid ◽  
Glucocorticoid Receptor ◽  
Transcriptional Activation ◽  
Mammalian Cells ◽  
Alpha Helix ◽  
Transactivation Domain ◽  
Hydrophobic Residues ◽  
Transactivation Activity ◽  
Reduced Activity ◽  
Helical Region

We have performed a mutagenesis analysis of the 58-amino-acid tau1-core peptide, which represents the core transactivation activity of the tau1 transactivation domain from the glucocorticoid receptor. Mutants with altered activity were identified by phenotypic screening in the yeast Saccharomyces cerevisiae. Most mutants with reduced activity had substitutions of hydrophobic amino acids. Most single-substitution mutants with reduced activity were localized near the N terminus of the tau1-core within a segment that has been shown previously to have a propensity for alpha-helix conformation, suggesting that this helical region is of predominant importance. The particular importance of hydrophobic residues within this region was confirmed by comparing the activities of alanine substitutions of the hydrophobic residues in this and two other helical regions. The hydrophobic residues were shown to be important for the transactivation activity of both the isolated tau1-core and the intact glucocorticoid receptor in mammalian cells. Rare mutations in helical regions I and II gave rise to increased transcriptional activation activity. These mutations increase the hydrophobicity of hydrophobic patches on each of these helices, suggesting a relationship between the hydrophobicity of the patches and transactivation activity. However, certain nonhydrophobic residues are also important for activity. Interestingly, helical region I partially matches a consensus motif found in the retinoic acid receptor, VP16, and several other activator proteins.

scholarly journals A Gain-of-Function TRPP2 Ion Channel Created by Mutating Single Amino Acid in the S5 Transmembrane Domain

2017 ◽  
Vol 112 (3) ◽  
pp. 249a-250a
Author(s):  
Mahmud Arif Pavel ◽  
Caixia Lv ◽  
Courtney Ng ◽  
Parul Kashyap ◽  
Clarissa Lam ◽  
...  
Keyword(s):  
Amino Acid ◽  
Ion Channel ◽  
Transmembrane Domain ◽  
Single Amino Acid ◽  
Gain Of Function

scholarly journals p53 mutations exhibit sex specific gain-of-function activity in gliomagenesis

2021 ◽  
Author(s):  
Nathan C Rockwell ◽  
Wei Yang ◽  
Nicole Warrington ◽  
Malachi Griffith ◽  
Obi L Griffith ◽  
...  
Keyword(s):  
Dna Binding ◽  
Expression Patterns ◽  
Metabolic Reprogramming ◽  
Mutant P53 ◽  
Small Male ◽  
Missense Mutations ◽  
P53 Mutations ◽  
Gain Of Function ◽  
Primary Mouse

The tumor suppressor TP53 is the most frequently mutated gene in cancer. Most TP53 mutations are missense mutations in the DNA-binding domain, which in addition to loss of canonical p53 activity, frequently confer gain-of-function (GOF) aberrant transcriptional activity through mutant p53 localization to non-canonical genes. GOF phenotypes differ by mutation and cell identity and are reported to include increased proliferation, migration, metabolic reprogramming, and therapy resistance. We found that several recurring p53 mutations exhibit a sex-bias in patients with glioblastoma (GBM). In vitro and in vivo analysis of three mutations, p53R172H, p53Y202C, and p53Y217C revealed sex differences in each mutation′s ability to transform primary mouse astrocytes. p53R172H exhibited a far greater ability to transform female astrocytes than males, p53Y202C transformed both male and female astrocytes with a small male bias, and p53Y217C only exhibited GOF transformation effects in male astrocytes. These phenotypic differences reflect an interaction between sex and GOF mutation to drive unique gene expression patterns in cancer pathways. We found that mutant p53 exhibits sex and mutation specific aberrant genomic localization to the transcriptional start sites of upregulated genes, whose promoter regions were enriched for different sets of transcription factor DNA-binding motifs. Together, our data establish a novel paradigm for sex specific mutant p53 GOF activity in GBM with implications for all cancer.

scholarly journals Evolution of New Function through a Single Amino Acid Change in the Yeast Repressor Sum1p

2008 ◽  
Vol 28 (8) ◽  
pp. 2567-2578 ◽  
Author(s):  
Alexias Safi ◽  
Kelley A. Wallace ◽  
Laura N. Rusche
Keyword(s):  
Amino Acid ◽  
Origin Recognition Complex ◽  
Amino Acid Change ◽  
Single Amino Acid ◽  
Wild Type ◽  
Gain Of Function ◽  
Critical Residue ◽  
Single Amino Acid Change ◽  
Interaction Domains ◽  
Self Association

ABSTRACT The SUM1-1 mutation is an example of a single amino acid change that results in new function. Wild-type Sum1p in Saccharomyces cerevisiae is a DNA-binding repressor that acts locally, whereas mutant Sum1-1p forms an extended repressive chromatin structure. By characterizing a panel of mutations in which various amino acids replaced the critical residue, threonine 988, we found that threonine was required for wild-type function and that in the absence of threonine the association of Sum1p with DNA was reduced. Isoleucine, the amino acid in mutant Sum1-1p, was required for the novel spreading property. Thus, the SUM1-1 mutation results in both a loss and a gain of function. The presence of isoleucine caused Sum1-1p to self-associate, a property that may promote spreading. In addition, isoleucine enabled Sum1-1p to associate with the origin recognition complex (ORC) and accumulate near ORC binding sites. Thus, both threonine and isoleucine at position 988 enable Sum1p to form intermolecular interactions. We propose that interaction domains may be hotspots for gain-of-function mutations because alterations in such domains have the potential to redirect a protein to new sets of binding partners. In addition, self-association of chromatin proteins may promote the formation of extended chromatin structures.

Attenuation of Getah virus by a single amino acid substitution at residue 253 of the E2 protein that might be part of a new heparan sulfate binding site on alphaviruses

2022 ◽  
Author(s):  
Ningning Wang ◽  
Xiaofeng Zhai ◽  
Xiaoling Li ◽  
Yu Wang ◽  
Wan-ting He ◽  
...  
Keyword(s):  
Amino Acid ◽  
Mouse Model ◽  
Heparan Sulfate ◽  
Binding Site ◽  
Amino Acid Substitution ◽  
Single Amino Acid ◽  
Virus Clearance ◽  
E2 Glycoprotein ◽  
Attachment Factor

The emergence of new epidemic variants of alphaviruses poses a public health risk. It is associated with adaptive mutations that often cause increased pathogenicity. Getah virus (GETV), a neglected and re-emerging mosquito-borne alphavirus, poses threat to many domestic animals and probably even humans. At present, the underlying mechanisms of GETV pathogenesis are not well defined. We identified a residue in the E2 glycoprotein that is critical for viral adsorption to cultured cells and pathogenesis in vivo . Viruses containing an arginine instead of a lysine at residue 253 displayed enhanced infectivity in mammalian cells and diminished virulence in a mouse model of GETV disease. Experiments in cell culture show that heparan sulfate (HS) is a new attachment factor for GETV, and the exchange Lys253Arg improves virus attachment by enhancing binding to HS. The mutation also results in more effective binding to glycosaminoglycan (GAG), linked to low virulence due to rapid virus clearance from the circulation. Localization of residue 253 in the 3D structure of the spike revealed several other basic residues in E2 and E1 in close vicinity that might constitute an HS-binding site different from sites previously identified in other alphaviruses. Overall, our study reveals that HS acts as the attachment factor of GETV and provides convincing evidence for an HS-binding determinant at residue 253 in the E2 glycoprotein of GETV, which contributes to infectivity and virulence. IMPORTANCE Due to decades of inadequate monitoring and lack of vaccines and specific treatment, a large number of people have been infected with alphaviruses. GETV is a re-emerging alphavirus that has the potential to infect humans. This specificity of the GETV disease, particularly its propensity for chronic musculoskeletal manifestations, underscores the need to identify the genetic determinants that govern GETV virulence in the host. Using a mouse model, we show that a single amino acid substitution at residue 253 in the E2 glycoprotein causes attenuation of the virus. Residue 253 might be part of a binding site for HS, a ubiquitous attachment factor on the cell surface. The substitution of Lys by Arg improves cell attachment of the virus in vitro and virus clearance from the blood in vivo by enhancing binding to HS. In summary, we have identified HS as a new attachment factor for GETV and the corresponding binding site in the E2 protein for the first time. Our research potentially improved understanding of the pathogenic mechanism of GETV and provided a potential target for the development of new attenuated vaccines and antiviral drugs.

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