engleski

POLY(ADP-RIBOSYL)ATION IN THE RED SEAWEED Chondrus crispus

Poly(ADP-ribosyl)ation is a post-translational modification of proteins involved in regulation of many cellular pathways. Poly(ADP-ribose) (PAR) consists of chains of repeating ADP-ribose nucleotide units and is synthesized by the family of enzymes called poly(ADP-ribose) polymerases (PARPs). This modification can be removed by the hydrolytic action of poly(ADP-ribose) glycohydrolase (PARG) and ADP-ribosylhydrolase 3 (ARH3). Hydrolytic activity of macrodomain proteins (MacroD1, MacroD2 and TARG1) is responsible for the removal of terminal ADP-ribose unit and for complete reversion of protein ADP-ribosylation. According to the phylogenetic distribution of proteins involved in PAR metabolism, it was proposed that the last common ancestor of all eukaryotes already possessed full set of proteins required for reversible PAR metabolism. To check whether this set was fully functional, we analyzed proteins from early branching eukaryotic lineage. The red algae (Rhodophyta) are one of the oldest groups of eukaryotic algae formed during the primary endosymbiosis event which enable the emergence of the first photosynthetic eukaryote. The red macroalgal fossil, 1.2 billion years old, provides the oldest evidence of multicellular, sexually reproducing eukaryote. Recently, genome of Chondrus crispus, or Irish moss, has been sequenced which was a prerequisite for positioning of red algae as excellent model organisms for understanding PARP evolution. Our analyses provides insight into the evolution of these important signaling systems, as well as providing evidence that red algae are appropriate genetic model organisms to study ancestral PARP(s), which are structurally and functionally similar to the highly sophisticated multifunctional enzymes which functions are usually associated with higher Metazoans.

DNA damage response ; Macrodomain ; PARP ; Poly(ADP‐ribose) ; red algae

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