The C-Terminal Region of G72 Increases D-Amino Acid Oxidase Activity

Abstract

The schizophrenia-related protein G72 plays a unique role in the regulation of d-amino acid oxidase (DAO) in great apes. Several psychiatric diseases, including schizophrenia and bipolar disorder, are linked to overexpression of DAO and G72. Whether G72 plays a positive or negative regulatory role in DAO activity, however, has been controversial. Exploring the molecular basis of the relationship between G72 and DAO is thus important to understand how G72 regulates DAO activity. We performed yeast two-hybrid experiments and determined enzymatic activity to identify potential sites in G72 involved in binding DAO. Our results demonstrate that residues 123–153 and 138–153 in the long isoform of G72 bind to DAO and enhance its activity by 22% and 32%, respectively. A docking exercise indicated that these G72 peptides can interact with loops in DAO that abut the entrance of the tunnel that substrate and cofactor must traverse to reach the active site. We propose that a unique gating mechanism underlies the ability of G72 to increase the activity of DAO. Because upregulation of DAO activity decreases d-serine levels, which may lead to psychiatric abnormalities, our results suggest a molecular mechanism involving interaction between DAO and the C-terminal region of G72 that can regulate N-methyl-d-aspartate receptor-mediated neurotransmission.

High-Throughput Screening Strategy Identifies Allosteric, Covalent Human D-Amino Acid Oxidase Inhibitor

“…This regulation has been reported as activation 5,23 by some researchers and inhibition by others. 7,8 In our hands, following a 30-min preincubation protocol and assaying hDAAO reaction product over the course of 60 min, pLG72 inhibited hDAAO with an IC 50 of approximately 0.9 µM (Suppl.…”

Regulating levels of the neuromodulator d‐serine in human brain: structural insight into pLG72 and d‐amino acid oxidase interaction

“…With the same purpose, an even shorter protein form was designed: pLG72 1–94 . The latter variant lacks the last 59 residues which are conserved in the products of isoforms 1–3 of G72 gene transcript (GI:126362975, GI:240120173, GI:240120029, respectively) , and eventually correspond to the form of the human protein expressed in G72 transgenic mice, reported as AFB69504.1 in the NCBI database (GI:377551785) . The protein corresponding to pLG72 72–153 is recognized as an interaction domain with DAAO by the Pfam database (PF15199, http://pfam.xfam.org/): this observation suggests that it could correspond to a structurally and functionally stable domain.…”

Expression of D-Amino Acid Oxidase (DAO/DAAO) and D-Amino Acid Oxidase Activator (DAOA/G72) during Development and Aging in the Human Post-mortem Brain

“…DAO activator (DAOA)/G72 (from now on addressed as DAOA) binds to DAO, but the effect of DAOA on DAO is controversial. This is because DAOA is reported to both increase (Chumakov et al, 2002; Chang et al, 2014) and decrease (Sacchi et al, 2008, 2011) the activity of DAO. DAOA is localized in mitochondria and reported to modulate its function (Kvajo et al, 2008; Sacchi et al, 2011; Otte et al, 2014).…”