Catherine J. Pears

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Poly adenosine diphosphate (ADP)-ribosylation (PARylation) by poly ADP-ribose (PAR) polymerases (PARPs) is an early response to DNA double-strand breaks (DSBs). In this paper, we exploit Dictyostelium discoideum to uncover a novel role for PARylation in regulating nonhomologous end joining (NHEJ). PARylation occurred at single-strand breaks, and two PARPs,(More)
GskA, the Dictyostelium GSK-3 orthologue, is modified and activated by the dual-specificity tyrosine kinase Zak1, and the two kinases form part of a signaling pathway that responds to extracellular cyclic AMP. We identify potential cellular effectors for the two kinases by analyzing the corresponding null mutants. There are proteins and mRNAs that are(More)
DNA double-strand breaks (DSBs) can be repaired by either homologous recombination (HR) or nonhomologous end-joining (NHEJ). In vertebrates, the first step in NHEJ is recruitment of the DNA-dependent protein kinase (DNA-PK) to DNA termini. DNA-PK consists of a catalytic subunit (DNA-PKcs) that is recruited to DNA ends by the Ku70/Ku80 heterodimer. Although(More)
The structural analysis of protein kinase C has led to the identification of a family of related gene products. This family of kinases consists of six unique genes that give rise to at least seven polypeptides. The high degree of conservation and the differential distribution of these mRNAs/proteins suggest that they perform distinct functions in vivo.(More)
BACKGROUND Increasing evidence suggests that individual isoforms of protein kinase C (PKC) play distinct roles in regulating platelet activation. METHODOLOGY/PRINCIPAL FINDINGS In this study, we focus on the role of two novel PKC isoforms, PKCdelta and PKCepsilon, in both mouse and human platelets. PKCdelta is robustly expressed in human platelets and(More)
BACKGROUND Cdk8 and its partner cyclin C form part of the mediator complex which links the basal transcription machinery to regulatory proteins. The pair are required for correct regulation of a subset of genes and have been implicated in control of development in a number of organisms including the social amoeba Dictyostelium discoideum. When feeding,(More)
Protein kinase C (PKC) is a family of serine/threonine kinases that play isoform-specific inhibitory and stimulatory roles in platelet activation. We show here that the pan-PKC inhibitor Ro31-8220 can be used to dissect these events following platelet activation by ADP. Submaximal concentrations of Ro31-8220 potentiated aggregation and dense granule(More)
ADP-ribosylation of proteins at DNA lesions by ADP-ribosyltransferases (ARTs) is an early response to DNA damage. The best defined role of ADP-ribosylation in the DNA damage response is in repair of single strand breaks (SSBs). Recently, we initiated a study of how ADP-ribosylation regulates DNA repair in Dictyostelium and found that two ARTs (Adprt1b and(More)