l-Isoaspartyl Methyltransferase Deficiency in Zebrafish Leads to Impaired Calcium Signaling in the Brain

Frontiers in Genetics

Rebeccah A. Warmack¹  Steven G. Clarke¹  Alexander D. Crawford³  Maria Lorena Cordero-Maldonado⁴  Mahsa Moein⁴  Jean-François Conrotte⁴  Carole L. Linster⁴  Remon Soliman⁴  Teresa G. Martins⁴  Alexander Skupin⁵ 

[1] Department of Chemistry and Biochemistry, The Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States;Department of Preclinical Sciences and Pathology, Norwegian University of Life Sciences, Oslo, Norway;Institute for Orphan Drug Discovery, Bremer Innovations- und Technologiezentrum, Bremen, Germany;Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg;University of California, San Diego, La Jolla, CA, United States;

关键词: isoaspartyl;    protein repair;    zebrafish;    calcium signaling;    HT22 cells;   

DOI  :  10.3389/fgene.2020.612343

来源: DOAJ

【 摘 要 】

Isomerization of l-aspartyl and l-asparaginyl residues to l-isoaspartyl residues is one type of protein damage that can occur under physiological conditions and leads to conformational changes, loss of function, and enhanced protein degradation. Protein l-isoaspartyl methyltransferase (PCMT) is a repair enzyme whose action initiates the reconversion of abnormal l-isoaspartyl residues to normal l-aspartyl residues in proteins. Many lines of evidence support a crucial role for PCMT in the brain, but the mechanisms involved remain poorly understood. Here, we investigated PCMT activity and function in zebrafish, a vertebrate model that is particularly well-suited to analyze brain function using a variety of techniques. We characterized the expression products of the zebrafish PCMT homologous genes pcmt and pcmtl. Both zebrafish proteins showed a robust l-isoaspartyl methyltransferase activity and highest mRNA transcript levels were found in brain and testes. Zebrafish morphant larvae with a knockdown in both the pcmt and pcmtl genes showed pronounced morphological abnormalities, decreased survival, and increased isoaspartyl levels. Interestingly, we identified a profound perturbation of brain calcium homeostasis in these morphants. An abnormal calcium response upon ATP stimulation was also observed in mouse hippocampal HT22 cells knocked out for Pcmt1. This work shows that zebrafish is a promising model to unravel further facets of PCMT function and demonstrates, for the first time in vivo, that PCMT plays a pivotal role in the regulation of calcium fluxes.

【 授权许可】

Unknown