Iron–Sulfur Cluster Biosynthesis in Algae with Complex Plastids. (2nd August 2018)

• Record Type: Journal Article
• Authors: Grosche, Christopher; Diehl, Angelika; Rensing, Stefan A; Maier, Uwe G
• Editors: Embley, Martin
• Is Part Of: Genome biology and evolution. Volume 10:Number 8(2018:Aug.)
• Page Start: 2061
• Page End: 2071
• Publication Date: 2018-08-02
• Subjects: iron–sulfur cluster -- cytosolic iron–sulfur protein assembly (CIA) -- periplastidal compartment -- Guillardia theta -- Bigelowiella natans -- Phaeodactylum tricornutum; Genomics -- Periodicals; Genes -- Periodicals; 572.8605
• DOI: 10.1093/gbe/evy156
• Languages: English
• ISSNs: 1759-6653

Abstract

Abstract: Plastids surrounded by four membranes harbor a special compartment between the outer and inner plastid membrane pair, the so-called periplastidal compartment (PPC). This cellular structure is usually presumed to be the reduced cytoplasm of a eukaryotic phototrophic endosymbiont, which was integrated into a host cell and streamlined into a plastid with a complex membrane structure. Up to date, no mitochondrion or mitochondrion-related organelle has been identified in the PPC of any representative. However, two prominent groups, the cryptophytes and the chlorarachniophytes, still harbor a reduced cell nucleus of symbiont origin, the nucleomorph, in their PPCs. Generally, many cytoplasmic and nucleus-located eukaryotic proteins need an iron–sulfur cofactor for their functionality. Beside some exceptions, their synthesis is depending on a so-called iron–sulfur complex (ISC) assembly machinery located in the mitochondrion. This machinery provides the cytoplasm with a still unknown sulfur component, which is then converted into iron–sulfur clusters via a cytosolic iron–sulfur protein assembly (CIA) machinery. Here, we investigated if a CIA machinery is present in mitochondrion-lacking PPCs. By using bioinformatic screens and in vivo-localizations of candidate proteins, we show that the presence of a PPC-specific CIA machinery correlates with the presence of a nucleomorph. Phylogenetic analyses of PPC- and host specific CIA components additionally indicate a complex evolution of the CIA machineries in organisms having plastids surrounded by four membranes.