The origin and evolution of the acidocalcisome and its interactions with other organelles

Abstract

Acidocalcisomes are acidic calcium stores that have been found from bacteria to human cells. They are rich in phosphorus compounds in the form of orthophosphate (Pi), pyrophosphate (PPi), and polyphosphate (polyP) and their acidity is maintained by proton pumps such as the vacuolar proton pyrophosphatase (V-H+-PPase, or VP1), the vacuolar proton ATPase (V-H+-ATPase), or both. Recent studies in trypanosomatids and in other species have revealed their role in phosphate metabolism, and cation and water homeostasis, as suggested by the presence of novel pumps, transporters, and channels. An important role in autophagy has also been described. The study of the biogenesis of acidocalcisomes as well as of the interactions of these lysosome-related organelles with other organelles have uncovered important roles in calcium signaling and osmoregulation. Significantly, despite conservation of acidocalcisomes across all of cellular life, there is evidence for intimate integration of these organelles with eukaryotic cellular functions, and which are directly relevant to parasites.

Native-state imaging of calcifying and noncalcifying microalgae reveals similarities in their calcium storage organelles

“…In coccolithophores, the molecular biology and biochemistry of such organelles is difficult to study. In other organisms, the situation is reversed, with the biology of concentrated calcium phosphate stores being well investigated ( 26 , 27 ), but the native ultrastructure and mineralogy remaining largely uncertain, since the methodology used for characterization involved dried or chemically fixed and/or resin-embedded cells. If commonalities exist in the mineralogy of Ca–P-rich phases in coccolithophores and biochemically better-characterized organisms, it would imply that the underlying cellular machinery may be related, which would help with elucidating the molecular underpinnings of coccolith formation.…”

Early stages of functional diversification in the Rab GTPase gene family revealed by genomic and localization studies inParameciumspecies

“…Because all three of these eukaryotic lineages are highly divergent from one another, these organelles may be ancestrally related, possibly through ancient lysosomal-related organelles (Docampo, 2015). This ancient relatedness may mean that the two pathways share similar components, facilitating functional switching of a Rab11 paralogue from one compartment to the other.…”

Polyphosphate: A Multifunctional Metabolite in Cyanobacteria and Algae

“…The main site of synthesis and storage of polyP is the acidic vacuole designated the acidocalcisome, discovered more than 100 years ago (Meyer, 1904;Vercesi et al, 1994) based on their visual prominence because they house densely stained polyP granules (Docampo et al, 2005;Miranda et al, 2008;Docampo, 2016;Docampo and Huang, 2016). These vacuoles have been characterized in disease causing trypanosomatids and apicomplexan parasites (Luo et al, 2004;Ruiz et al, 2004b;Fang et al, 2007a;Moreno and Docampo, 2009;Madeira da Silva and Beverley, 2010;Li and He, 2014;Kohl et al, 2018) and algae (Aksoy et al, 2014;Goodenough et al, 2019), and have similar characteristics to vacuoles in fungi (Gerasimaite et al, 2017) and animal cells (Ruiz et al, 2004a;Huizing et al, 2008;Muller et al, 2009;Moreno-Sanchez et al, 2012;Morrissey, 2012).…”