jcem3144.pdf (1.81 MB)
Rapid proteasomal degradation of mutant proteins is the primary mechanism leading to tumorigenesis in patients with missense AIP mutations
journal contribution
posted on 2023-06-21, 06:01 authored by Laura C Hernández-Ramírez, Federico Martucci, Rhodri M L Morgan, Giampaolo Trivellin, Daniel Tilley, Nancy Ramos-Guajardo, Donato Iacovazzo, Fulvio D'Acquisto, Chrisostomos ProdromouChrisostomos Prodromou, Márta KorbonitsCONTEXT The pathogenic effect of AIP mutations (AIPmuts) in pituitary adenomas is incompletely understood. We have identified the primary mechanism of loss of function for missense AIPmuts. OBJECTIVE To analyze the mechanism/speed of protein turnover of wild-type (WT) and missense AIP variants, correlating protein half-life with clinical parameters. DESIGN Half-life and protein-protein interaction experiments and cross-sectional analysis of AIPmut positive patients' data were performed. SETTING Clinical academic research institution. PATIENTS Data was obtained from our cohort of pituitary adenoma patients and literature-reported cases. INTERVENTIONS Protein turnover of endogenous AIP in two cell lines and fifteen AIP variants overexpressed in HEK293 cells was analyzed via cycloheximide chase and proteasome inhibition. GST pull-down and quantitative mass spectrometry identified proteins involved in AIP degradation; results were confirmed by co-immunoprecipitation and gene knockdown. Relevant clinical data was collected. MAIN OUTCOME MEASURES Half-life of WT and mutant AIP proteins and its correlation with clinical parameters. RESULTS Endogenous AIP half-life was similar in HEK293 and lymphoblastoid cells (43.5 and 32.7h). AIP variants were divided in stable proteins (median 77.7h [IQR 60.7-92.9]), and those with short (27h [21.6-28.7]) or very short (7.7h [5.6-10.5]) half-life; proteasomal inhibition rescued the rapid degradation of mutant proteins. The experimental half-life significantly correlated with age at diagnosis of acromegaly/gigantism (r=0.411, P=0.002). The FBXO3-containing SCF complex was identified as the E3 ubiquitin-ligase recognizing AIP. CONCLUSIONS AIP is a stable protein, driven to ubiquitination by the SCF complex. Enhanced proteasomal degradation is a novel pathogenic mechanism for AIPmuts, with direct implications for the phenotype.
History
Publication status
- Published
File Version
- Published version
Journal
The Journal of clinical endocrinology and metabolismISSN
1945-7197Publisher
Endocrine SocietyExternal DOI
Issue
8Volume
101Page range
3144 -3154Department affiliated with
- Biochemistry Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2016-06-06First Open Access (FOA) Date
2016-11-02First Compliant Deposit (FCD) Date
2016-11-02Usage metrics
Categories
No categories selectedKeywords
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC