The nuclear protein PH5P of the inter-alpha-inhibitor superfamily: a missing link between poly(ADP-ribose)polymerase and the inter-alpha-inhibitor family and a novel actor of DNA repair?
Poly(ADP-ribose)polymerase is a nuclear NAD-dependent enzyme and an essential nick sensor involved in cellular processes where nicking and rejoining of DNA strands are required. The inter-alpha-inhibitor family is comprized of several plasma proteins that all harbor one or more so-called heavy chains designated H1-H4. The latter originate from precursor polypeptides H1P-H4P whose upper two thirds are highly homologous. We now describe a novel protein that includes (i) a so-called BRCT domain found in many proteins involved in DNA repair, (ii) an area that is homologous to the NAD-dependent catalytic domain of poly(ADP-ribose)polymerase, (iii) an area that is homologous to the upper two thirds of precursor polypeptides H1P-H4P and (iv) a proline-rich region with a potential nuclear localization signal. This protein now designated PH5P points to as yet unsuspected links between poly(ADP-ribose)polymerase and the inter-alpha-inhibitor family and is likely to be involved in DNA repair.
Jean
L
L
INSERM Unit-78 and Institut Fédératif de Recherches Multidisciplinaires sur les Peptides, Rouen, France.
Risler
J L
JL
Nagase
T
T
Coulouarn
C
C
Nomura
N
N
Salier
J P
JP
D000510:Alpha-Globulins / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D004260:DNA Repair; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*
D000510:Alpha-Globulins; D009687:Nuclear Proteins; C118687:PARP4 protein, human; C011877:inter-alpha-inhibitor; D011065:Poly(ADP-ribose) Polymerases