Home About us Contact
|
Home About us Contact | ||
|
|
||
Phosphatase Domain (phosphatase + domain)
Selected AbstractsBCCIP associates with the receptor protein tyrosine phosphatase PTPµJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 4 2008Polly J. Phillips-Mason Abstract The receptor protein tyrosine phosphatase PTPµ belongs to a family of adhesion molecules that contain cell,cell adhesion motifs in their extracellular segments and catalytic domains within their intracellular segments. The ability of PTPµ both to mediate adhesion and exhibit enzymatic activity makes PTPµ an excellent candidate to transduce signals in response to cell,cell adhesion. In an effort to identify downstream signaling partners of PTPµ, we performed a modified yeast two-hybrid screen using the first tyrosine phosphatase domain of PTPµ as bait. We isolated an interacting clone encoding BRCA2 and CDKN1A interacting protein (BCCIP) from a HeLa cell library. BCCIP is a p21 and BRCA2 interacting protein that has been shown to play roles in both cell cycle arrest and DNA repair. In this manuscript, we confirm the interaction between BCCIP and PTPµ identified in yeast using in vitro biochemical studies and characterize BCCIP as a PTPµ binding protein. We demonstrate that BCCIP is phosphorylated by the Src tyrosine kinase and dephosphorylated by the PTPµ tyrosine phosphatase in vitro. Furthermore, we show that BCCIP is required for both the permissive and repulsive functions of PTPµ in neurite outgrowth assays, suggesting BCCIP and PTPµ are in a common signal transduction pathway. J. Cell. Biochem. 105: 1059,1072, 2008. © 2008 Wiley-Liss, Inc. [source] The cell differentiation protein SpoIIE contains a regulatory site that controls its phosphatase activity in response to asymmetric septationMOLECULAR MICROBIOLOGY, Issue 4 2002Andrea Feucht Summary Starvation induces Bacillus subtilis to initiate a simple, two-cell developmental process that begins with an asymmetric cell division. Activation of the first compartment-specific transcription factor, ,F, is coupled to this morphological event. SpoIIE, a bifunctional protein, is essential for the compartment-specific activation of ,F and also has a morphogenic activity required for asymmetric cell division. SpoIIE consists of three domains: a hydrophobic N-terminal domain, which targets the protein to the membrane; a central domain, involved in oligomerization of SpoIIE and interaction with the cell division protein FtsZ; and a C-terminal domain comprising a PP2C protein phosphatase. Here, we report the isolation of mutations at the very beginning of the central domain of spoIIE, which are capable of activating ,F independently of septum formation. Purified mutant proteins showed the same phosphatase activity as the wild-type protein in vitro. The mutant proteins were fully functional in respect of their localization to sites of asymmetric septation and support of asymmetric division. The data provide strong evidence that the phosphatase domain of SpoIIE is tightly regulated in a way that makes it respond to the formation of the asymmetric septum. [source] A mutant form of PTEN linked to autismPROTEIN SCIENCE, Issue 10 2010Roberta E. Redfern Abstract The tumor suppressor, phosphatase, and tensin homologue deleted on chromosome 10 (PTEN), is a phosphoinositide (PI) phosphatase specific for the 3-position of the inositol ring. PTEN has been implicated in autism for a subset of patients with macrocephaly. Various studies identified patients in this subclass with one normal and one mutated PTEN gene. We characterize the binding, structural properties, activity, and subcellular localization of one of these autism-related mutants, H93R PTEN. Even though this mutation is located at the phosphatase active site, we find that it affects the functions of neighboring domains. H93R PTEN binding to phosphatidylserine-bearing model membranes is 5.6-fold enhanced in comparison to wild-type PTEN. In contrast, we find that binding to phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) model membranes is 2.5-fold decreased for the mutant PTEN in comparison to wild-type PTEN. The structural change previously found for wild-type PTEN upon interaction with PI(4,5)P2, is absent for H93R PTEN. Consistent with the increased binding to phosphatidylserine, we find enhanced plasma membrane association of PTEN-GFP in U87MG cells. However, this enhanced plasma membrane association does not translate into increased PI(3,4,5)P3 turnover, since in vivo studies show a reduced activity of the H93R PTEN-GFP mutant. Because the interaction of PI(4,5)P2 with PTEN's N-terminal domain is diminished by this mutation, we hypothesize that the interaction of PTEN's N-terminal domain with the phosphatase domain is impacted by the H93R mutation, preventing PI(4,5)P2 from inducing the conformational change that activates phosphatase activity. [source] Inactivation of the CTD phosphatase-like gene OsCPL1 enhances the development of the abscission layer and seed shattering in riceTHE PLANT JOURNAL, Issue 1 2010Hyeonso Ji Summary Although susceptibility to seed shattering causes severe yield loss during cereal crop harvest, it is an adaptive trait for seed dispersal in wild plants. We previously identified a recessive shattering locus, sh-h, from the rice shattering mutant line Hsh that carries an enhanced abscission layer. Here, we further mapped sh-h to a 34-kb region on chromosome 7 by analyzing 240 F2 plants and five F3 lines from the cross between Hsh and Blue&Gundil. Hsh had a point mutation at the 3, splice site of the seventh intron within LOC_Os07g10690, causing a 15-bp deletion of its mRNA as a result of altered splicing. Two transferred DNA (T-DNA) insertion mutants and one point mutant exhibited the enhanced shattering phenotype, confirming that LOC_Os07g10690 is indeed the sh-h gene. RNA interference (RNAi) transgenic lines with suppressed expression of this gene exhibited greater shattering. This gene, which encodes a protein containing a conserved carboxy-terminal domain (CTD) phosphatase domain, was named Oryza sativa CTD phosphatase-like 1 (OsCPL1). Subcellular localization and biochemical analysis revealed that the OsCPL1 protein is a nuclear phosphatase, a common characteristic of metazoan CTD phosphatases involved in cell differentiation. These results demonstrate that OsCPL1 represses differentiation of the abscission layer during panicle development. [source] The 1.35,Å resolution structure of the phosphatase domain of the suppressor of T-cell receptor signaling protein in complex with sulfateACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 6 2010Jean Jakoncic The suppressor of T-cell signaling (Sts) proteins are multidomain proteins that negatively regulate the signaling of membrane-bound receptors, including the T-cell receptor (TCR) and the epidermal growth-factor receptor (EGFR). They contain at their C-terminus a 2H-phosphatase homology (PGM) domain that is responsible for their protein tyrosine phosphatase activity. Here, the crystal structure of the phosphatase domain of Sts-1, Sts-1PGM, was determined at pH 4.6. The asymmetric unit contains two independent molecules and each active site is occupied by a sulfate ion. Each sulfate is located at the phosphate-binding site and makes similar interactions with the catalytic residues. The structure suggests an explanation for the lower Michaelis,Menten constants at acidic pH. [source] Expression, crystallization and preliminary crystallographic analysis of the PAS domain of RsbP, a stress-response phosphatase from Bacillus subtilisACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 6 2009Masatomo Makino RsbP, a regulator of RNA polymerase ,B activity in Bacillus subtilis, is a phosphatase containing a Per,Arnt,Sim (PAS) domain in its N-terminal region that is expected to sense energy stresses such as carbon, phosphate or oxygen starvation. Energy-stress signals are transmitted to the PAS domain and activate the C-terminal phosphatase domain of RsbP, leading to activation of the downstream anti-anti-,B factor RsbV. Finally, the general stress response is induced to protect the cells against further stresses. The recombinant PAS domain of RsbP was crystallized by the sitting-drop vapour-diffusion technique using 40% PEG 400 as a precipitant. The crystals belonged to space group P21, with unit-cell parameters a = 55.2, b = 71.7, c = 60.2,Å, , = 92.1°. Diffraction data were collected to a resolution of 1.6,Å. [source] Characterization of Phosphatase and Tensin Homolog expression in the mosquito Aedes aegypti: Six splice variants with developmental and tissue specificityINSECT MOLECULAR BIOLOGY, Issue 3 2007Michael A. Riehle Abstract Phosphatase and tensin homologue (PTEN), an inhibitor of insulin signalling, was characterized in Aedes aegypti. Surprisingly, six splice variants were identified: three with alternative terminal exons (AaegPTEN2 : 3 : 6) and three formed by intron retention (AaegPTEN1 : 4 : 5). All variants encoded active phosphatase domains. Variants with alternative terminal exons also encoded C2 and COOH-domains, and AaegPTEN6 encoded a PDZ binding motif. These three variants also had unique expression patterns. AaegPTEN2 was expressed primarily in the ovary. AaegPTEN3 was predominant in heads and midguts, and throughout development, except early embryogenesis. AaegPTEN6 was expressed in fat body, ovaries, and throughout development. Intron retention variants were weakly expressed in most samples. These expression patterns suggest that AaegPTEN variants play unique roles in regulating insulin's pleiotropic effects. [source] | |||||||||||||