ACINUS: a putative integrant of programmed cell death in plants

Programmed cell death (PCD) is a key process for the maintaining of homeostasis in organisms, with a plethora of different types of PCD occurring in pluricellular organisms, such as apoptosis, ferroptosis, necroptosis and others. The response to stimulus and its nature, such as developmental and environmental signals, culminates in a specific type of PCD being activated. Among the factors involved in apoptosis-like PCD processes, there are caspases, proteases that actively cleaves protein targets in aspartic residue sites, which are predominant in metazoans. Among caspase targets, the apoptotic chromatin condensation inducer in the nucleus (Acinus, or ACIN1) has been described as necessary for apoptosis occurrence. Acinus was first described in human cells, together with its isoforms (Acinus-L, Acinus-S and Acinus-S’), being primarily indicated as a key factor for chromatin condensation during PCD but also pointed out as a regulator in the metabolism of DNA and RNA. In model plant Arabidopsis thaliana, an Acinus ortholog is associated to mRNA splicing and the vernalization process, binding to splicing factors, chromatin remodelers and transcriptional regulators, but no studies have shown participation of such ortholog in plant PCD. Recent studies in agronomically relevant plant species have indicated the possible association of Acinus orthologs with pathogen response and PCD in plants. Thus, in this short review we compiled all works related to Acinus, where we emphasize the high structural conservation of Acinus orthologs in animals and plants. Based on the information presented in this work we aim to encourage future works focused on putative Acinus function and role during plant PCD processes, gathering information for use in future plant PCD researches.