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Substrate specificity of soluble and membrane‐associated ADP‐ribosyltransferase ART2.1
Author(s) -
Zheng Xuexiu,
Morrison Alan R.,
Chung AnSik,
Moss Joel,
Bortell Rita
Publication year - 2006
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.20722
Subject(s) - biochemistry , nad+ kinase , membrane protein , enzyme , biology , chemistry , microbiology and biotechnology , membrane
ADP‐ribosyltransferases (ARTs) are a family of enzymes that catalyze the covalent transfer of an ADP‐ribose moiety, derived from NAD, to an amino acid of an acceptor protein, thereby altering its function. To date, little information is available on the protein target specificity of different ART family members. ART2 is a T‐cell‐specific transferase, attached to the cell surface by a glycosylphosphatidylinositol (GPI) anchor, and also found in serum. Here we investigated the role of ART2 localization in serum or on the cell surface, or solubilized with detergents or enzymes, on its target protein specificity. We found that detergent solubilization of cell membranes, or release of ART2 by phosphoinositide‐specific phospholipase C treatment, altered the ability of ART2 to ADP‐ribosylate high or low molecular weight histone proteins. Similarly, soluble recombinant ART2 (lacking the GPI anchor) showed a different histone specificity than did cell‐bound ART2. When soluble ART2 was incubated with serum proteins in the presence of [ 32 P]‐labeled NAD, several serum proteins were ADP‐ribosylated in a thiol‐specific manner. Mass spectrometry of labeled proteins identified albumin and transferrin as ADP‐ribosylated proteins in serum. Collectively, these studies reveal that the membrane or solution environment of ART2 plays a pivotal role in determining its substrate specificity. J. Cell. Biochem. 98: 851–860, 2006. © 2006 Wiley‐Liss, Inc.