Crosstalk between the stress axes: Identification of the NIPA - p53 interaction

Abstract: The F-box protein NIPA (nuclear interaction partner of ALK) defines a nuclear SCF-type ubiquitin ligase contributing to the timing of mitotic entry. Previous studies also point to a role for NIPA in the DNA damage pathway as part of the nuclear pore complex. In the present study, it was aimed to identify the role and functional impact of NIPA in response to DNA damage and its underlying mechanism.
In initial experiments, it was found that loss of NIPA impairs proper repair of DNA double strand breaks (DSBs) indicated by significantly elevated γH2AX foci in primary MEFs. Furthermore, it could be demonstrated that NIPA is phosphorylated in response to DNA damage by DNA-damaging agents and UV irradiation in a dose-dependent manner. Proteomic phosphorylation site analysis revealed serine 329 to be specifically phosphorylated in response to DNA damage and ATR could be identified as the responsible kinase inducing this phosphorylation. This phosphorylation might have a regulatory function for NIPA as the NIPA S329 phosphorylation-deficient mutant is functionally inactive in the DNA damage response (DDR) pathway: Similar to NIPA-deficient cells, NIPA S329A-phosphorylation-deficient mutant cells present increased cell proliferation due to a significant reduction in apoptosis induction after severe DNA damage. These effects might be explained by a significant decrease of p53 protein expression in NIPA-deficient cells. Interestingly, cells lacking NIPA displayed a mislocalization of p53 from the nucleus to the cytoplasm in response to DNA damage leading to impaired p53 function in the DDR pathway.
This mislocalization could be explained by the ability of NIPA to control the p53 nuclear export by direct interaction with p53. The interaction of NIPA and p53 could be related to severe DNA damage and is dependent on NIPA S329 phosphorylation. Moreover, it could be demonstrated that NIPA disrupts the export complex formation of p53 with the export protein CRM1. By binding to p53, NIPA reduces the ability of CRM1 to interact with p53, thereby inhibiting export complex formation. Additionally, NIPA decreases the interaction of CRM1 with the nucleoporin TPR at the NPC.
The impaired nuclear stabilization of p53 in NIPA-deficient cells might also impact the susceptibility of these cells to oncogenic transformation as indicated by increased proliferation of NIPA-deficient c-Myc- and k-Ras-positive cells in vitro, thereby indicating a relevant role for NIPA in tumor suppression.
These results uncover a novel mechanism for the regulation of the subcellular localization of p53 in response to DNA damage and reveal NIPA as an important modulator of the p53 DNA damage pathway

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch
• Anmerkungen: Universität Freiburg, Dissertation, 2019

Klassifikation und Themen

• Schlagwort: p53 protein ; Identification ; Crosstalk ; Protein p53

Beteiligte, Orts- und Zeitangaben

• Ereignis: Veröffentlichung
• (wo): Freiburg
• (wer): Universität
• (wann): 2019
• Urheber: Müller-Rudorf, Alina
• Beteiligte Personen und Organisationen: Illert, Anna Lena ; Zeiser, Robert ; Albert-Ludwigs-Universität Freiburg. Fakultät für Biologie

Weitere Informationen

• DOI: 10.6094/UNIFR/151221
• URN: urn:nbn:de:bsz:25-freidok-1512215
• Rechteinformation: Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 25.03.2025, 13:45 MEZ