Expanding the clinical spectrum of PPP3CA variants - alternative isoforms matter

Abstract Background the protein phosphatase 3 catalytic subunit alpha (PPP3CA) gene encodes for the alpha isoform of the calcineurin catalytic subunit, which controls the phosphorylation status of many targets. Currently, 23 pathogenic variants of PPP3CA are known, with clinical manifestations varyi...

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Main Authors: Silvia Castiglioni, Laura Pezzoli, Lidia Pezzani, Antonella Lettieri, Elisabetta Di Fede, Anna Cereda, Silvia Ancona, Andrea Gallina, Elisa Adele Colombo, Chiara Parodi, Paolo Grazioli, Esi Taci, Donatella Milani, Maria Iascone, Valentina Massa, Cristina Gervasini
Format: Article
Language:English
Published: BMC 2024-12-01
Series:Orphanet Journal of Rare Diseases
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Online Access:https://doi.org/10.1186/s13023-024-03507-0
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author Silvia Castiglioni
Laura Pezzoli
Lidia Pezzani
Antonella Lettieri
Elisabetta Di Fede
Anna Cereda
Silvia Ancona
Andrea Gallina
Elisa Adele Colombo
Chiara Parodi
Paolo Grazioli
Esi Taci
Donatella Milani
Maria Iascone
Valentina Massa
Cristina Gervasini
author_facet Silvia Castiglioni
Laura Pezzoli
Lidia Pezzani
Antonella Lettieri
Elisabetta Di Fede
Anna Cereda
Silvia Ancona
Andrea Gallina
Elisa Adele Colombo
Chiara Parodi
Paolo Grazioli
Esi Taci
Donatella Milani
Maria Iascone
Valentina Massa
Cristina Gervasini
author_sort Silvia Castiglioni
collection DOAJ
description Abstract Background the protein phosphatase 3 catalytic subunit alpha (PPP3CA) gene encodes for the alpha isoform of the calcineurin catalytic subunit, which controls the phosphorylation status of many targets. Currently, 23 pathogenic variants of PPP3CA are known, with clinical manifestations varying by mutation type and domain. Results through whole exome sequencing, we found two de novo variants in PPP3CA: a frameshift variant predicted leading to a truncated protein in Pt.1 and a splicing variant in Pt.2 associated with mild phenotype. PPP3CA is ubiquitously expressed with tissue-specificity of; namely, splicing isoform 1 prevailing over isoform 2 in the central nervous system. By analyzing isoform distribution in patient-derived cell lines, we highlight a skewed expression of both isoforms in Pt.1, whereas only isoform 2 shows a moderate reduction in Pt.2. In contrast, we did not observe significant abundance changes at the protein level. Cell lines derived from Pt.1 showed a reduced proliferation, associated with an increase in cell death and the upregulation of the unfolded protein response (UPR) pathway. Conclusion data suggest that an aberrant PPP3CA protein in Pt.1 could lead to UPR activation resulting in increased cell death. In Pt.2 an imbalance between the two main isoforms possibly explains the peculiar pathological manifestations, such as a moderate developmental delay.
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spelling doaj-art-e46a9e6885aa4e15898dd68b20342f012025-08-20T02:31:52ZengBMCOrphanet Journal of Rare Diseases1750-11722024-12-011911910.1186/s13023-024-03507-0Expanding the clinical spectrum of PPP3CA variants - alternative isoforms matterSilvia Castiglioni0Laura Pezzoli1Lidia Pezzani2Antonella Lettieri3Elisabetta Di Fede4Anna Cereda5Silvia Ancona6Andrea Gallina7Elisa Adele Colombo8Chiara Parodi9Paolo Grazioli10Esi Taci11Donatella Milani12Maria Iascone13Valentina Massa14Cristina Gervasini15Department of Health Sciences, Università degli Studi di MilanoMedical Genetics Laboratory, Papa Giovanni XXIII HospitalPediatrics, Papa Giovanni XXIII HospitalDepartment of Health Sciences, Università degli Studi di MilanoDepartment of Health Sciences, Università degli Studi di MilanoPediatrics, Papa Giovanni XXIII HospitalDepartment of Health Sciences, Università degli Studi di MilanoDepartment of Health Sciences, Università degli Studi di MilanoDepartment of Health Sciences, Università degli Studi di MilanoDepartment of Health Sciences, Università degli Studi di MilanoDepartment of Health Sciences, Università degli Studi di MilanoDepartment of Health Sciences, Università degli Studi di MilanoFondazione IRCCS Ca’ Granda Ospedale Maggiore PoliclinicoMedical Genetics Laboratory, Papa Giovanni XXIII HospitalDepartment of Health Sciences, Università degli Studi di MilanoDepartment of Health Sciences, Università degli Studi di MilanoAbstract Background the protein phosphatase 3 catalytic subunit alpha (PPP3CA) gene encodes for the alpha isoform of the calcineurin catalytic subunit, which controls the phosphorylation status of many targets. Currently, 23 pathogenic variants of PPP3CA are known, with clinical manifestations varying by mutation type and domain. Results through whole exome sequencing, we found two de novo variants in PPP3CA: a frameshift variant predicted leading to a truncated protein in Pt.1 and a splicing variant in Pt.2 associated with mild phenotype. PPP3CA is ubiquitously expressed with tissue-specificity of; namely, splicing isoform 1 prevailing over isoform 2 in the central nervous system. By analyzing isoform distribution in patient-derived cell lines, we highlight a skewed expression of both isoforms in Pt.1, whereas only isoform 2 shows a moderate reduction in Pt.2. In contrast, we did not observe significant abundance changes at the protein level. Cell lines derived from Pt.1 showed a reduced proliferation, associated with an increase in cell death and the upregulation of the unfolded protein response (UPR) pathway. Conclusion data suggest that an aberrant PPP3CA protein in Pt.1 could lead to UPR activation resulting in increased cell death. In Pt.2 an imbalance between the two main isoforms possibly explains the peculiar pathological manifestations, such as a moderate developmental delay.https://doi.org/10.1186/s13023-024-03507-0PPP3CAcalcineurinDEE-91LCLsUPS
spellingShingle Silvia Castiglioni
Laura Pezzoli
Lidia Pezzani
Antonella Lettieri
Elisabetta Di Fede
Anna Cereda
Silvia Ancona
Andrea Gallina
Elisa Adele Colombo
Chiara Parodi
Paolo Grazioli
Esi Taci
Donatella Milani
Maria Iascone
Valentina Massa
Cristina Gervasini
Expanding the clinical spectrum of PPP3CA variants - alternative isoforms matter
Orphanet Journal of Rare Diseases
PPP3CA
calcineurin
DEE-91
LCLs
UPS
title Expanding the clinical spectrum of PPP3CA variants - alternative isoforms matter
title_full Expanding the clinical spectrum of PPP3CA variants - alternative isoforms matter
title_fullStr Expanding the clinical spectrum of PPP3CA variants - alternative isoforms matter
title_full_unstemmed Expanding the clinical spectrum of PPP3CA variants - alternative isoforms matter
title_short Expanding the clinical spectrum of PPP3CA variants - alternative isoforms matter
title_sort expanding the clinical spectrum of ppp3ca variants alternative isoforms matter
topic PPP3CA
calcineurin
DEE-91
LCLs
UPS
url https://doi.org/10.1186/s13023-024-03507-0
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