Isoaspartate formation and irreversible aggregation of collapsin response mediator protein 2: implications for the etiology of epilepsy and age-related cognitive decline.

Autor: Zhu JX; Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, CA, 92697-3900, USA.; Shanghai Reinovax Biologics Co. LTD, 5th Floor, Building I, 367 Sheng Rong Road, Pudong New District, Shanghai, 201210, China., Aswad DW; Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, CA, 92697-3900, USA. dwaswad@uci.edu.
Jazyk: angličtina
Zdroj: Amino acids [Amino Acids] 2024 Dec 24; Vol. 57 (1), pp. 5. Date of Electronic Publication: 2024 Dec 24.
DOI: 10.1007/s00726-024-03435-0
Abstrakt: Collapsin response mediator protein 2 (CRMP2) functions in the genesis and activity of neuronal connections in mammalian brain. We previously reported that a protein coincident with CRMP2 on 2D-gels undergoes marked accumulation of abnormal L-isoaspartyl sites in brain extracts of mice missing the repair enzyme, protein L-isoaspartyl methyltransferase (PIMT). To confirm and explore the significance of isoaspartyl damage in CRMP2, we expressed and purified recombinant mouse CRMP2 (rCRMP2). A polyclonal antibody made against the recombinant protein precipitated CRMP2 from brain extracts of PIMT-KO mice, but not from WT mice, suggesting that (1) the rCRMP2 antigen underwent significant isoAsp formation in the process of antibody production and (2) the isoAsp form of CRMP2 is considerably more immunogenic than the native protein. In vitro aging of rCRMP2 at pH 7.4, 37 °C for 0-28 days led to robust accumulation of isoAsp sites that were repairable by PIMT, and also induced a progressive accumulation of apparent dimers and higher-mass oligomers as judged by SDS-PAGE. A similar pattern of CRMP2 aggregation was observed in mice, with levels increasing throughout the lifespan. We conclude that CRMP2 is indeed a major target of PIMT-mediated protein repair in the brain; that isoAsp forms of CRMP2 are highly immunogenic; and that CRMP2 dysfunction makes a significant contribution to neuropathology in the PIMT-KO mouse.
Competing Interests: Declarations. Conflict of interests: The authors declare no competing interests. Ethical approval: The use of mice in this study was approved by the UC Irvine Institutional Animal Care and Use Committee. Consent for publication: Not applicable.
(© 2024. The Author(s).)
Databáze: MEDLINE
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