Metazoan evolution of glutamate receptors reveals unreported phylogenetic groups and divergent lineage-specific events

Abstract

Glutamate receptors are divided in two unrelated families: ionotropic (iGluR), driving synaptic transmission, and metabotropic (mGluR), which modulate synaptic strength. The present classification of GluRs is based on vertebrate proteins and has remained unchanged for over two decades. Here we report an exhaustive phylogenetic study of GluRs in metazoans. Importantly, we demonstrate that GluRs have followed different evolutionary histories in separated animal lineages. Our analysis reveals that the present organization of iGluRs into six classes does not capture the full complexity of their evolution. Instead, we propose an organization into four subfamilies and ten classes, four of which have never been previously described. Furthermore, we report a sister class to mGluR classes I-III, class IV. We show that many unreported proteins are expressed in the nervous system, and that new Epsilon receptors form functional ligand-gated ion channels. We propose an updated classification of glutamate receptors that includes our findings.

New Insights Into the Evolutionary History of Melatonin Receptors in Vertebrates, With Particular Focus on Teleosts

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How many sirtuin genes are out there? evolution of sirtuin genes in vertebrates with a description of a new family member*

“…The lack of description of family members is not uncommon; it could be mainly due to the absence in model species and/or appropriate evolutionary analyses. In the literature, there are examples in which more comprehensive analyses provide a better description of the membership composition of gene families, including previously unknown family members with an ancient evolutionary origin (Castro et al 2012;Wichmann et al 2016;Céspedes et al 2017;Ramos-Vicente et al 2018;Opazo, Kuraku, et al 2019; . The availability of species with different gene repertoires, as a result of a birth-and-death process, could be seen as a natural experiment (Albertson et al 2009) that helps understand the evolutionary fate of duplicated genes, as they are capable of fulfilling the biological functions associated to the gene family but with a different combination of paralogs.…”

Feedback to the future: motor neuron contributions to central pattern generator function

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