The Pathogenic A391E Mutation in FGFR3 Induces a Structural Change in the Transmembrane Domain Dimer

Mudumbi, Krishna C.; Julius, Ayse; Herrmann, Jana; Li, Edwin

doi:10.1007/s00232-013-9563-6

Cited by 4 publications

(4 citation statements)

References 30 publications

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“…We scanned the PilO transmembrane and found that there is a conserved Small-xxx-Small motif present at residues 40 and 44 (A40xxxA44). This motif has been shown to play an important role in helix-helix dimerization in transmembrane proteins (22,23); thus, we hypothesized that this domain might be mediating interaction between the α-helix of PilO and the SadC TMD. To identify mutations in the A40xxxA44 motif of PilO that impact PilO-SadC interaction, we used two different approaches.…”

Section: Resultsmentioning

confidence: 99%

Interaction between the type 4 pili machinery and a diguanylate cyclase fine-tune c-di-GMP levels during early biofilm formation

Webster

Lee

Schmidt

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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To initiate biofilm formation, it is critical for bacteria to sense a surface and respond precisely to activate downstream components of the biofilm program. Type 4 pili (T4P) and increasing levels of c-di-GMP have been shown to be important for surface sensing and biofilm formation, respectively; however, mechanisms important in modulating the levels of this dinucleotide molecule to define a precise output response are unknown. Here, using macroscopic bulk assays and single-cell tracking analyses of Pseudomonas aeruginosa, we uncover a role of the T4P alignment complex protein, PilO, in modulating the activity of the diguanylate cyclase (DGC) SadC. Two-hybrid and bimolecular fluorescence complementation assays, combined with genetic studies, are consistent with a model whereby PilO interacts with SadC and that the PilO–SadC interaction inhibits SadC’s activity, resulting in decreased biofilm formation and increased motility. Using single-cell tracking, we monitor both the mean c-di-GMP and the variance of this dinucleotide in individual cells. Mutations that increase PilO–SadC interaction modestly, but significantly, decrease both the average and variance in c-di-GMP levels on a cell-by-cell basis, while mutants that disrupt PilO–SadC interaction increase the mean and variance of c-di-GMP levels. This work is consistent with a model wherein P. aeruginosa uses a component of the T4P scaffold to fine-tune the levels of this dinucleotide signal during surface commitment. Finally, given our previous findings linking SadC to the flagellar machinery, we propose that this DGC acts as a bridge to integrate T4P and flagellar-derived input signals during initial surface engagement.

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Section: Resultsmentioning

confidence: 99%

Interaction between the type 4 pili machinery and a diguanylate cyclase fine-tune c-di-GMP levels during early biofilm formation

Webster

Lee

Schmidt

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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“…Since there have been no case reports describing the patients who had the p.L377R or the p.S378N variant independently, we do not know whether these variants are pathogenic or not. A previous in vitro study by ToxR plasmids carrying the FGFR3 transmembrane domain demonstrated that the substitutions of the p.S378 to glycine, alanine, cysteine, or isoleucine showed no or very little changes in the dimerization of the receptor (Mudumbi, Julius, Herrmann, & Li, ), although the effect of the p.S378N was not examined. They also demonstrated that p.S378I significantly altered the dimerization propensity of the receptor with the p.A391E, which is a pathogenic mutation causing Crouzon syndrome with acanthosis nigricans.…”

Section: Discussionmentioning

confidence: 99%

Severe achondroplasia due to two de novo variants in the transmembrane domain of FGFR3 on the same allele: A case report

Nagata

Matsushita

Mishima

et al. 2020

Molec Gen & Gen Med

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Background Achondroplasia (ACH), the most common form of short‐limbed skeletal dysplasia, is caused by gain‐of‐function mutations in the fibroblast growth factor receptor 3 (FGFR3) gene. More than 97% of patients result from a heterozygous p.G380R mutation in the FGFR3 gene. We present here a child who had two de novo variants in the FGFR3 on the same allele, a common p.G380R mutation and a novel p.S378N variant. Methods A 3‐year‐old Japanese girl born from non‐consanguineous healthy parents showed more severe clinical and radiological phenotypes than classic ACH, including severe short‐limbed short stature with marked ossification defects in the metaphysis and epiphysis, hydrocephalus and cervicomedullary compression due to foramen magnum stenosis, prolonged pulmonary hypoplasia, and significant delay in the gross motor development. Genomic DNA was extracted from the proband and whole‐exome sequencing was performed. The variants were subsequently confirmed by Sanger sequencing. Results Mutation analysis demonstrated that the proband had p.S378N (c.1133G>A) and p.G380R (c.1138G>A) variants in the FGFR3 gene. Both variants were not detected in her parents and therefore considered de novo. An allele‐specific PCR was developed in order to determine whether these mutations were on the same allele (cis) or on different alleles (trans). The c.1138G>A mutation was found in the PCR product generated with the primer for the mutant 1133A, but it was not detected in the product with the wild‐type 1133G, confirming that p.S378N and p.G380R variants were located on the same allele (cis). Conclusion This is the second case who had two FGFR3 variants in the transmembrane domain on the same allele. The p.S378N variant may provide an additive effect on the activating receptor with the p.G380R mutation and alter the protein function, which could be responsible for the severe phenotype of the present case.

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“…Another interesting case is variant c.1172C>A (p.A391E). It is located in the transmembrane domain of the receptor and has been described to lead to constitutive receptor activation already in the absence of ligand (Chen et al, 2011; Mudumbi et al, 2013; Sarabipour and Hristova, 2016). We observed the same effect when measuring the GRB2 recruitment and we also showed that this variant cannot be further triggered by the addition of ligand.…”

Section: Discussionmentioning

confidence: 99%

Activating mutations in FGFR3 are associated with clonal expansion events and high de novo rates in the male germline

Moura

Hartl

Brumovska

et al. 2022

Preprint

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Delayed fatherhood results in a higher risk to inherit a new germline mutation that might result in a congenital disorder in the offspring. In particular, some FGFR3 mutations increase in frequency with age, but there are still a large number of uncharacterized FGFR3 mutations that could be expanding in the male germline with potentially early or late-onset effects in the offspring. Here, we investigated the mutation frequency in the DNA of human testis and sperm and the activation state of the expressed mutant protein of eight different FGFR3 variants categorized by ClinVar as deleterious, benign, or not reported. Overall, the ligand-independent activation of the mutant protein resulted in a increased number of mutant sperm; although, strong activating mutations did not necessarily result in the highest frequencies. Moreover, only two mutants c.952G>A and c.1620C>A showed an increase with the donor's age; the latter also forming larger clonal expansions in the testis. We also showed that the prediction of deleteriousness of a mutation is not always accurate, and similar in silico scores can reflect either a gain-of-function or loss-of-function. Our approach led to the discovery of two novel variants c.1261G>A and c.952G>A to have promiscuous FGFR3 activation and increased mutation frequencies in the male germline. The large fraction of donors with mutations suggests a high de novo rate potentially explained by a selective advantage before the maturation of the male germline. This sequence-function study provides important data for the evaluation and interpretation of variants with relevant clinical implications

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The Pathogenic A391E Mutation in FGFR3 Induces a Structural Change in the Transmembrane Domain Dimer

Cited by 4 publications

References 30 publications

Interaction between the type 4 pili machinery and a diguanylate cyclase fine-tune c-di-GMP levels during early biofilm formation

Interaction between the type 4 pili machinery and a diguanylate cyclase fine-tune c-di-GMP levels during early biofilm formation

Severe achondroplasia due to two de novo variants in the transmembrane domain of FGFR3 on the same allele: A case report

Activating mutations in FGFR3 are associated with clonal expansion events and high de novo rates in the male germline

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