Abstract
Y-box-binding protein 1 (YB-1) is a multifunctional positively charged protein that interacts with DNA or RNA and poly(ADP-ribose) (PAR). YB-1 is poly(ADP-ribosyl)ated and stimulates poly(ADP-ribose) polymerase 1 (PARP1) activity. Here, we studied the mechanism of YB-1-dependent PAR synthesis by PARP1 in vitro using biochemical and atomic force microscopy assays. PAR synthesis activity of PARP1 is known to be facilitated by co-factors such as Mg2+. However, in contrast to an Mg2+-dependent reaction, the activation of PARP1 by YB-1 is accompanied by overall up-regulation of protein PARylation and shortening of the PAR polymer. Therefore, YB-1 and cation co-factors stimulated PAR synthesis in divergent ways. PARP1 autoPARylation in the presence of YB-1 as well as trans-PARylation of YB-1 are greatly affected by the type of damaged DNA, suggesting that PARP1 activation depends on the formation of a PARP1–YB-1–DNA ternary complex. An unstructured C-terminal part of YB-1 involved in an interaction with PAR behaves similarly to full-length YB-1, indicating that both DNA and PAR binding are involved in the stimulation of PARP1 activity by YB-1. Thus, YB-1 is likely linked to the regulation of PARylation events in cells via an interaction with PAR and damaged DNA.
Highlights
Poly(ADP-ribose) polymerases (PARPs) belong to the family of ADP-ribosyl transferase enzymes, which catalyse the synthesis of a poly(ADP-ribose) (PAR) polymer using NAD+ as a substrate [1,2,3]
We have previously reported that Y-box-binding protein 1 (YB-1) can stimulate poly(ADP-ribose) (PAR) synthesis and poly(ADP-ribose) polymerase 1 (PARP1) autoPARylation in the absence of divalent cations, which act as co-factors for PAR synthesis [19,32]
Two possible mechanisms have been proposed to explain the regulation of PARP1 activity by YB-1: direct interaction of YB-1 either with damaged DNA or with PAR polymer synthesised by PARP1 [32]
Summary
Poly(ADP-ribose) polymerases (PARPs) belong to the family of ADP-ribosyl transferase enzymes, which catalyse the synthesis of a poly(ADP-ribose) (PAR) polymer using NAD+ as a substrate [1,2,3]. Taking into account the key role of PARP1 in the regulation of DNA repair and in the maintenance of genomic stability [1,3,8,32], special attention is given to proteins participating in the modulation of PARP1 auto- and trans-PARylation activity in vivo [33,34] In this regard, a number of recently identified RNA-binding proteins with intrinsically disordered regions implicated in the DNA damage response because of an interaction with PAR or its PARylation deserve research attention [35,36]. Functional interplay between PARP1 and YB-1 may affect the application of PARP1 inhibitors in cancer treatment [38]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
