Pathological and physiological roles of ADP-ribosylation: established functions and new insights.

The posttranslational modification of proteins with poly(ADP-ribose) was discovered in the sixties. Since then, we have learned that the enzymes involved, the so-called poly(ADP-ribosyl)polymerases (PARPs), are transferases which use cofactor NAD to transfer ADP-ribose to their targets. Few PARPs are able to create poly(ADP-ribose), whereas the majority transfers a single ADP-ribose.

Protein and RNA ADP-ribosylation detection is influenced by sample preparation and reagents used.

The modification of substrates with ADP-ribose (ADPr) is important in, for example, antiviral immunity and cancer. Recently, several reagents were developed to detect ADP-ribosylation; however, it is unknown whether they recognise ADPr, specific amino acid-ADPr linkages, or ADPr with the surrounding protein backbone. We first optimised methods to prepare extracts containing ADPr-proteins and observe that depending on the amino acid modified, the modification is heatlabile.

The nucleolar DExD/H protein Hel66 is involved in ribosome biogenesis in Trypanosoma brucei.

The biosynthesis of ribosomes is a complex cellular process involving ribosomal RNA, ribosomal proteins and several further trans-acting factors. DExD/H box proteins constitute the largest family of trans-acting protein factors involved in this process. Several members of this protein family have been directly implicated in ribosome biogenesis in yeast.