Chronophin Dimerization Is Required for Proper Positioning of Its Substrate Specificity Loop

Abstract

Background:The role of homodimerization in the family of C2a-capped HAD phosphatases is unknown. Results: Chronophin homodimerization is required for proper positioning of the substrate specificity loop and for substrate dephosphorylation. Conclusion:The specificity of chronophin is allosterically controlled by a homophilic intermolecular interaction. Significance: Our results reveal a general principle of how HAD hydrolase dimerization can contribute to substrate specificity.

Reversible oxidation controls the activity and oligomeric state of the mammalian phosphoglycolate phosphatase AUM

“…The first aspartate in this signature motif serves as the nucleophile and forms a phosphoaspartate intermediate during catalysis [20,21]. Primary functions of the cap domain are to mediate solvent exclusion/inclusion during the catalytic cycle, and to provide specificity determinants for substrate coordination [22,23]. According to their size, structure and insertion site in the core domain, caps are subdivided into C0, C1 and C2a/C2b modules [12].…”

Functional Diversity of Haloacid Dehalogenase Superfamily Phosphatases from Saccharomyces cerevisiae

“…5). Previous analysis of the available structures of HAD-like hydrolases indicated that ϳ60% of them are likely to form dimers or higher oligomers, whereas the other proteins appeared to be monomeric (124). In the human PLP/protein phosphatase chronophin, homodimerization is essential for the proper positioning of a conserved His residue in the substrate specificity loop (124).…”

“…Previous analysis of the available structures of HAD-like hydrolases indicated that ϳ60% of them are likely to form dimers or higher oligomers, whereas the other proteins appeared to be monomeric (124). In the human PLP/protein phosphatase chronophin, homodimerization is essential for the proper positioning of a conserved His residue in the substrate specificity loop (124). The structures of four yeast HADs suggested a monomeric state for RHR2, SDT1, and UTR4 and a dimeric state for YKR070W with the cap domain of one protomer extending/reaching close to the core domain of the second protomer (Fig.…”

“…Substrate saturation experiments with 2-deoxyribose-5-phosphate and purified YKR070W mutant proteins revealed a significant reduction both in cooperativity (k H ϭ 1.1-1.2) and substrate binding (K m ϭ 0.4 -0.5 mM) in the F132A, F132Y, and F132H proteins (k H ϭ 1.1-1.2) compared with the wild type YKR070W (k H ϭ 1.4 and K m ϭ 0.3 mM). Although a recent analysis of the available structures of HAD dimers has led to the suggestion that the adjacent HAD protomers do not share active site residues (124), all of these structures show the presence of a conserved aromatic residue homologous to the YKR070W Phe-132 positioned close to the substrate binding site of another protomer. These HAD proteins include the mouse chronophin (Phe-152, PDB code 4BX3) and HDHD2 (Tyr-124, PDB code 2HO4), human LHPP (Tyr-132, PDB code 2X4D), PH1952 from Pyrococcus horikoshii (Tyr-132, PDB code 1ZJJ), and AF0374 from Archaeoglobus fulgidus (Phe-128, PDB code 3QGM).…”

Chronophin coordinates cell leading edge dynamics by controlling active cofilin levels

“…CIN is a haloacid dehydrogenase-type phosphatase, a family of enzymes with activity in mammalian cells that has been poorly characterized. CIN dephosphorylates a very limited number of substrates (33) and as opposed to SSH, has little phosphatase activity toward LIMK both in vitro and in vivo; thus, it seems to be the more specific activator of cofilin (29,30). CIN exhibits several predicted interaction motifs potentially linking it to regulation by PI3-kinase and phospholipase Cγ (PLCγ), both of which have been implicated in signaling to cofilin activation in vivo in MTLn3 adenocarcinoma cells (10,34).…”