Phospho-epitope binding by the BRCT domains of hPTIP controls multiple aspects of the cellular response to DNA damage
Authors: Rachel Toth
Ivan M Munoz
Paul A Jowsey
John Rouse
Journal: Nucleic Acids Research (2007)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: hPTIP; 53BP1; DNA damage; ATM; phosphorylation
Affiliations: MRC Protein Phosphorylation Unit, Sir James Black Centre, University of Dundee, Dundee DD1 5EH, Scotland, UK.

Abstract:  Human (h)PTIP plays important but poorly understood roles in cellular responses to DNA damage. hPTIP interacts with 53BP1 tumour suppressor but only when 53BP1 is phosphorylated by ATM after DNA damage although the mechanism(s) and significance of the interaction of these two proteins are unclear. Here, we pinpoint a single ATM-phosphorylated residue in 53BP1--Ser25--that is required for binding of 53BP1 to hPTIP. Binding of phospho-Ser25 to hPTIP in vitro and in vivo requires two closely apposed pairs of BRCT domains at the C-terminus of hPTIP and neither pair alone can bind to phospho-Ser25, even though one of these BRCT pairs in isolation can bind to other ATM-phosphorylated epitopes. Mutations in 53BP1 and in hPTIP that prevent the interaction of the two proteins, render cells hypersensitive to DNA damage and weaken ATM signalling. The C-terminal BRCT domains of hPTIP are also required for stable retention of hPTIP at sites of DNA damage but this appears to be independent of binding to 53BP1. Thus, the BRCT domains of hPTIP play important roles in the cellular response to DNA damage. 

Retracted: No

PubPeer comments:
 A detailed independent investigation into Fig. 6C by academics concluded that although some tracks are similar due to the use of pre-cast gels and standardised methodology and reagents, there is no evidence of duplication. However, for the avoidance of any doubt we present here an independent experiment demonstrating similar results. ![file] In investigating Fig. 6C, duplicated control lanes in Fig 1C were noted. A new figure to correct the mistake in Fig 1C has been offered to the editor of Nucleic Acids Research and is presented here to maintain the integrity of the research record. This correction does not alter the conclusions of the article. ![file] , 
  A detailed independent investigation into Fig. 6C by academics concluded that although some tracks are similar due to the use of pre-cast gels and standardised methodology and reagents, there is no evidence of duplication.  It is difficult to explain the similarities between the bands marked in the yellow and red rectangles in figure 6C. , 
 Thank you for responding Mr Rouse. In your independent repeat demonstrating the results are sound, were pre-cast gels and standardised methodology and reagents used? If so, can you indicate anywhere on the diagram where this has resulted in identically shaped bands, or bands which, once mirrored, have an identical shape? , 
 #2 Are the academics providing the  detailed independent investigation into Fig. 6C by academics willing to share their names? , 
 Looks a lot like an unacknowledged splice in the Chk2 pThr68 letterbox, between the hPTIPP- 120 and hPTIP-WT 0 lanes. More visible after color reversal. ![file] , 
 Are we able to see the original gels before they were assembled? For me, it is all when and good getting someone to repeat the experiment but frankly, this could have been a lucky coincidence. , 
 http: www.lifesci.dundee.ac.uk news 2017 oct 24 john-rouse-wins-2017-fanconi-anemia-research-fund-discovery-award , 
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 Figure 1C. Much more similar than expected. ![file] ,