Dataset Information

Ciliopathy-associated missense mutations in IFT140 are hypomorphic and have edgetic effects on protein interaction networks

ABSTRACT: The mechanisms underlying recessive Mendelian diseases and the interplay between genotype and phenotype still need to be better understood. It is therefore necessary to characterise the functional effects of missense mutations at the protein level. Here we focus on missense mutations in the intraflagellar transport protein IFT140, which forms part of the IFT complex A (IFT-A), a crucial component of the ciliary machinery. Mutations in IFT140 can cause a vast spectrum of diseases belonging to the group of ciliopathies, reaching from isolated retinal dystrophy to severe skeletal abnormalities and multi-organ diseases such as Mainzer-Saldino and Jeune syndrome. We hypothesise that missense mutations in IFT140 are hypomorphic leading to quantitative effects on a subset of protein-protein interactions. This may affect complex stability as well as perturbations of protein interaction networks. In this work we assessed how 24 missense mutations in IFT140 affect interactions with other IFT and effector proteins using affinity purification coupled to mass spectrometry. Our data reveals that several mutations in IFT140 are hypomorphic and disrupt the stability of the IFT-A complex to varying degrees in a quantitative way. Allelic combination and the degree of IFT-A complex disruption in analysed missense mutations correlates with the severity of the observed phenotype in a subset of patients. In addition, we show that a distinct subset of mutations in IFT140 shows edgetic effects by disrupting specific PPIs rather than causing a total loss of IFT-A binding. This is the case e.g. with the disease-associated protein TULP3 which is involved in cilia-dependent sonic hedgehog signalling.

INSTRUMENT(S): Orbitrap Fusion

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: Tina Beyer

LAB HEAD: Dr. Karsten Boldt

PROVIDER: PXD044186 | Pride | 2025-05-06

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	TLE3219-S02-A-NSF_RAF1_01.raw	Raw
	TLE3219-S06-A-NSF_WT_01.raw	Raw
	TLE3219-S07-A-NSF_V108M_01.raw	Raw
	TLE3219-S08-A-NSF_G140R_01.raw	Raw
	TLE3219-S10-A-NSF_S939P_01.raw	Raw

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Publications

Ciliopathy-Associated Missense Mutations in IFT140 are Tolerated by the Inherent Resilience of the IFT Machinery.

Beyer Tina T Diwan Gaurav D GD Leonhard Tobias T Dahlke Katrin K Klose Franziska F Stehle Isabel F IF Seda Marian M Bolz Sylvia S Woerz Franziska F Russell Robert B RB Jenkins Dagan D Ueffing Marius M Boldt Karsten K

Molecular & cellular proteomics : MCP 20250127 3

Genotype-phenotype correlations of rare diseases are complicated by low patient number, high phenotype variability, and compound heterozygosity. Mutations may cause instability of single proteins, and affect protein complex formation or overall robustness of a specific process in a given cell. Ciliopathies offer an interesting case for studying genotype-phenotype correlations as they have a spectrum of severity and include diverse phenotypes depending on different mutations in the same protein. ...[more]

PMID: 39880085

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Project description:Cilia assembly, maintenance and the localization of signal-transduction proteins necessitate a functioning intraflagellar transport (IFT). The IFT machinery moves cargo along a microtubule scaffold from the proximal to the distal end of the cilium. This anterograde transport is facilitated by a large multiprotein complex IFT-B, which consists of 16 proteins in total and recruits motor protein Kinesin-2 for active movement. TTC30A and TTC30B are integral components of this complex and were shown before to have redundant function in context of IFT. One paralogue could compensate the loss of the other, preventing the disruption of IFT-B and thus a severe ciliogenesis defect with no formation of the cilium. Affinity-based protein complex analysis of endogenously tagged cells, generated via CRISPR/Cas9 system as described before, revealed paralogue specific protein interactors proposing the involvement of TTC30A or TTC30B in other ciliary functions, particularly Sonic hedgehog signaling (Shh). Defects in this ciliary signaling pathway are often correlated to synpolydactyly, which intriguingly is also linked to a rare TTC30 variant. In this study we focus on the so far unknown interaction of TTC30A with protein kinase A catalytic subunit α PRKACA, which is a negative regulator of Shh pathway. For an in-depth analysis of this unique interaction and the influence on Shh, we used previously, via the CRISPR/Cas9 system, generated TTC30A or B single- and double-knockout hTERT-RPE1 cells as well as rescue cells harboring the TTC30 mutation. Our systematic approach revealed the paralogue specific influence of TTC30A KO and mutated TTC30A on the activity of PRKACA as well as the uptake of Smoothened into the cilium resulting in a downregulation of Sonic hedgehog signaling. Affinity-based protein complex analysis of wildtype versus mutated TTC30A or TTC30B uncovered differences in interaction pattern. These interactome alterations combined with Shh downregulation suggest a possible mechanism of how mutant TTC30A and respectively TTC30A KO are linked to synpolydactyly.

Project description:Study Smoking and COPD are associated with decreased mucociliary clearance and healthy smokers have shorter cilia in the large airway than nonsmokers. Intraflagellar transport (IFT) is the process by which cilia are produced and maintained. We assessed expression of IFT-related genes in smokers and nonsmokers and evaluated cilia length in the large and small airway of nonsmokers, healthy smokers, and smokers with COPD. Methods Airway epithelium was obtained via bronchoscopic brushing. Affymetrix microarrays were used to evaluate IFT gene expression in 2 independent data sets from large and small airway. Cilia length was assessed by measuring 100 cilia (10 cilia on each of 10 cells) per subject. Results All 40 IFT genes were expressed in the human large and small airway epithelium. In the large airway, 10 IFT genes were down-regulated and 1 up-regulated in smokers. In the small airway, 11 genes were down-regulated and 3 up-regulated in smokers. A set of 8 IFT genes was down-regulated in both data sets. In the large and small airway epithelium, cilia were significantly shorter in healthy smokers than nonsmokers, and significantly shorter in COPD smokers than in both healthy smokers and nonsmokers. Answer to the Question These results support the concept that loss of cilia length contributes to defective mucociliary clearance in COPD, and that smoking-induced changes in expression of IFT genes may be one mechanism of abnormally short cilia in smokers. Strategies to normalize cilia length may be an important avenue for novel COPD therapies. Gene expression was assessed for 40 intraflagellar transport related genes in the LAE of nonsmokers (n=21) and healthy smokers (n=31) and the SAE of an independent group of nonsmokers (n=28) and healthy smokers (n=69). Cilia length was assessed in a total of 228 airway epithelium samples, including 120 LAE samples and 108 SAE samples; a subset of the 228 samples is represented among the 149 samples in this Series.