Ca2+-regulated mitochondrial carriers of ATP-Mg2+/Pi: Evolutionary insights in protozoans

In addition to its uptake across the Ca2+ uniporter, intracellular calcium signals can stimulate mitochondrial metabolism activating metabolite exchangers of inner membrane belonging carrier family (SLC25). One these Ca2+-regulated carriers (CaMCs) are reversible ATP-Mg2+/Pi transporters, or SCaMCs, required for maintaining optimal adenine nucleotide (AdN) levels in matrix representing an alternative transporter ADP/ATP translocases (AAC). This CaMC has a distinctive Calmodulin-like (CaM-like) domain fused that makes transport activity strictly dependent on cytosolic signals. Here we investigate about origin analysing distribution and features unicellular eukaryotes. Unexpectedly, find two types carriers, canonical ones shortened variants lacking CaM-like domain. Phylogenetic analysis shows both SCaMC have common origin, unrelated AACs, suggesting turn recurrent losses regulatory module occurred different phyla. They excluding show more limited less conservation than AACs. Interestingly, truncated found almost exclusively parasitic protists, such as apicomplexans, kinetoplastides animal-patogenic oomycetes, green algae, lost could be related certain life-styles. addition, intricate structural diversity may associated with their pathogenicity. The consequences functions new SCaMC-b discussed.