Disease relevance of PHOSPHO1

• Using multiparameter flow cytometry, we monitored phospho-protein responses to environmental cues in acute myeloid leukemia at the single cell level [1].
• In contrast, when myc-tagged human eNOS carried a mutation at the Akt phosphorylation site (Ser1177), O-linked N-acetylglucosamine modification was unchanged by hyperglycemia and phospho-eNOS was undetectable [2].
• RESULTS: An inverse correlation was observed between phospho-STAT-3 and SOCS-3 protein expression in cholangiocarcinoma [3].
• Levels of phospho-p38 mitogen-activated protein kinase did not change as a result of either hypoxia or irradiation [4].
• We previously showed, by immunohistochemistry with phospho-specific antibodies, increased phosphorylation (activation) of Akt (Ser(473)) [phosphorylated Akt (pAkt)] in high-Gleason grade prostate cancer (Malik SN, et al., Clin Cancer Res 2002;8:1168-71) [5].

Psychiatry related information on PHOSPHO1

• In addition, substantia nigra neurons from patients with incidental Lewy body disease, Parkinson disease (PD), and diffuse Lewy body dementia (DLB) display abnormal phospho-ERK accumulations in the form of discrete cytoplasmic granules [6].
• Phospho-tau/total tau ratio in cerebrospinal fluid discriminates Creutzfeldt-Jakob disease from other dementias [7].
• In Alzheimer's disease (AD), neuronal thread protein (NTP) accumulates in cortical neurons and colocalizes with phospho- tau-immunoreactive cytoskeletal lesions that correlate with dementia [8].
• In patients with vascular dementia, phospho-tau 181 levels were not different from controls but were significantly lower than in patients with manifest AD [9].
• The data showed that the immobility time of rats that received maternal deprivation in early life was longer than that of control rats and Western blot analysis also showed that the amygdala phospho-MAPK level in maternally deprived rats was almost two times higher than in control rats [10].

High impact information on PHOSPHO1

• Altered growth factor responses in phospho-protein-driven signaling networks are crucial to cancer cell survival and pathology [1].
• Thus, single cell measurements of phospho-protein responses reveal shifts in signaling potential of a phospho-protein network, allowing for categorizing of cell network phenotypes by multidimensional molecular profiles of signaling [1].
• Expression of Ser(473) phospho Akt in primary human breast cancers statistically correlated with expression of p27 in tumor cytosol [11].
• Immunostaining with phospho-specific antibodies in mammalian cells reveals mitotic phosphorylation of H3 Thr 3 in prophase and its dephosphorylation during anaphase [12].
• Moesin is a widely expressed phospho-protein that links many transmembrane molecules to the cortical actin cytoskeleton [13].

Chemical compound and disease context of PHOSPHO1

• Here, we report that paclitaxel, a microtubule-damaging agent, induces phosphorylation of p70S6K at threonine 421 and serine 424 (T421/S424) in a concentration- and time-dependent manner in multiple breast and ovarian cancer cell lines demonstrated by a T421/S424 phospho-p70S6K antibody [14].
• We demonstrate here that exposing A549 human alveolar type 2 adenocarcinoma cells to hyperoxia (95% O(2)) for 0.5-24 h time-dependently increases phospho-ERK, phospho-p53(Ser15), p53, and p21(CIP1) protein levels [15].
• Isoelectrofocusing of erythrocyte galactose 1 phospho uridyl transferase in a family with both galactosemia and Duarte variants [16].
• A short leucine-rich sequence in the Borna disease virus p10 protein mediates association with the viral phospho- and nucleoproteins [17].
• This latter phospho-protein is involved in the initiation of hydroxyapatite crystallisation and its expression in breast cancer has been associated to the presence of hydroxyapatite microcalcifications [18].

Biological context of PHOSPHO1

• Instead, we propose that two fully conserved Asp residues (Asp43 and Asp123), not present in PSPs contribute to substrate specificity in PHOSPHO1 [19].
• Mapping of the PHOSPHO1 genes to regions of HSA17q21.3, MMU11 and GGA27 that exhibit conservation of synteny provides strong evidence that they are orthologous [20].
• Chicken PHOSPHO1 was mapped by SSCP analysis to position 44 cM on GGA27, adjacent to the HOXB@ (44 cM) and COL1A1 (36 cM) loci [20].
• Further comparative modelling reveals that the active sites of PHOSPHO1 and PHOSPHO2 are very similar, but surprisingly, recombinant PHOSPHO2 hydrolyses phosphoethanolamine and phosphocholine relatively poorly [21].
• We also show that Asp43 and Asp123, residues that line the substrate-binding site in our PHOSPHO1 model, are important for substrate hydrolysis [21].

Anatomical context of PHOSPHO1

• PHOSPHO1 is a recently identified phosphatase expressed at high levels in the chicken growth plate and which may be involved in generating inorganic phosphate for skeletal matrix mineralization [20].
• We isolated MVs from growth plate chondrocytes and confirmed the presence of high levels of PHOSPHO1 by immunoblotting [22].
• Whole-mount in situ hybridization indicated that PHOSPHO1 expression occurred prior to E6.5 and was initially restricted to the bone collar within the mid-shaft of the diaphysis of long bones but by E11.5 expression was observed over the entire length of the diaphysis [22].
• Ventricular ependymal cilia are crucial for directing cerebrospinal fluid flow, and ependyma of Tg mice exhibited disrupted cilia with increased phospho-CREB immunoreactivity [23].
• The osmosensitivity of GAP43 furnishes a mechanistic framework that links axon elongation with phospho inositide metabolism, spontaneous triggering of cytosolic Ca(2+) transients and the regulation of actin dynamics and motility at the growth cone in response to temporal and local mechanical forces [24].

Associations of PHOSPHO1 with chemical compounds

• PHOSPHO1, a phosphoethanolamine/phosphocholine phosphatase, is upregulated in mineralising cells and is thought to be involved in the generation of inorganic phosphate for bone mineralisation [21].
• We show here that PHOSPHO1 exhibits high specific activities toward phosphoethanolamine (PEA) and phosphocholine (PCho) [25].
• Alcian blue/alizarin red staining revealed that PHOSPHO1 expression seen in the primary regions of ossification preceded the deposition of mineral, suggesting that it is involved in the initial events of mineral formation [22].
• Expression of PHOSPHO1, like TNAP activity, was found to be up-regulated in MVs isolated from chondrocytes induced to differentiate by the addition of ascorbic acid [22].
• Phosphopeptide mapping identified a major autophosphorylation site, phospho (p)Thr-219, between the tandem C1 domains of the regulatory fragment in protein kinase C (PKC)theta [26].

Physical interactions of PHOSPHO1

• A phospho-specific antibody was developed that only bound to full-length p21 protein after phosphorylation in vitro at Ser(146), and this reagent was further used to demonstrate that the inactive isoform of p21 recovered from Sf9 cells treated with phosphatase inhibitors had been phosphorylated in vivo at Ser(146) [27].
• We found that the phospho-mimic mutation T341D increases binding with itself or the N-terminal half of ECT2 [28].
• Mutational analyses and phospho-peptide mapping suggested that the SH2 domain of Csk may preferentially bind to ITIM Y562 of CD85j; yet, mutation to phenylalanine of Y533, Y614, and Y644 also significantly reduced Csk recruitment by CD85j [29].
• Although phospho-dependent binding is important for Chk2 activity, previously uncharacterized phospho-independent FHA domain interactions appear to be the primary target of oncogenic lesions [30].
• A native phospho-specific IgG binding assay was developed for quantitating the extent of p53 phosphorylation at Ser(315) where one, two, three, or four phosphates/tetramer could be defined after in vitro phosphorylation by cyclin-dependent protein kinases [31].

Enzymatic interactions of PHOSPHO1

• Phospho amino acid analysis of the Mr 180,000 receptor band shows that only tyrosine residues are phosphorylated when A431 membranes are treated with either EGF or PMA [32].
• Evidence was provided that GO/MGO upregulated MKP-1 activity that in turn dephosphorylated possibly co-aggregated phospho-ERK efficiently for inactivation [33].
• Further, we examined the localization of the phosphorylated form of cofilin using phospho-specific antibody raised against phosphorylated cofilin [34].
• METHODS: We examined the submembrane localization of NaPi-IIa in opossum kidney (OK-N2) cells that stably expressed human NaPi-IIa, and searched for a PTH-induced specific phosphorylating substrate on their membrane microdomains by immunoblotting with specific antibody against phospho substrates of protein kinases [35].
• Interleukin-4/13 and transforming growth factor-beta-activated cells were identified by specific antibodies to phosphorylated (phospho-) signal transducer and activator of transcription 6 and phospho-Smad2, respectively [36].

Co-localisations of PHOSPHO1

• HU and CAMPT treatment also led to the formation of RPA foci that co-localized with phospho-Nbs1 foci [37].

Regulatory relationships of PHOSPHO1

• Addition of the inhibitor-of-protein serine/threonine phosphatases, okadaic acid, blocks the ATRA-mediated reduction in TGF-beta-induced phospho-Smad2 and shifts the differentiation toward monocytic end points [38].
• However, the phospho-mimic mutation at T341 weakly stimulates the catalytic activity of ECT2 as detected by serum response element reporter gene assays [28].
• In the present study, these claims have been explored by the genotyping of previously associated markers in CYP46A1 in three independent northern European case-control series encompassing 1323 individuals and including approximately 400 patients with measurements of CSF Abeta42 and phospho-tau protein levels [39].
• The transient overexpression of TSP-1 up-regulated alpha2I collagen and phospho-Smad3 levels in normal fibroblasts but had no major effect on scleroderma fibroblasts [40].
• The stabilized p53 in E7-expressing cells is in a wild-type conformation and the same number of phospho-forms is present [41].

Other interactions of PHOSPHO1

• PHOSPHO2 is a putative phosphatase sharing 42% sequence identity with PHOSPHO1 [21].
• We have identified homologous proteins in a number of species and have modelled human PHOSPHO1 based upon the crystal structure of phosphoserine phosphatase (PSP) from Methanococcus jannaschii [19].
• Immunofluorescence microscopy using phospho-antibodies indicates that APC phosphorylation is initiated in prophase during nuclear uptake of cyclin B1 [42].
• Specific down-regulation of interleukin-12 signaling through induction of phospho-STAT4 protein degradation [43].
• Using small-molecule inhibitors of GSK3, site-specific mutants of p130, and phospho-specific antibodies, we demonstrate here that GSK3 phosphorylates p130 during G0 [44].

Analytical, diagnostic and therapeutic context of PHOSPHO1

• Using a degenerate RT-PCR approach a fragment of human PHOSPHO1 was cloned [20].
• Using a combination of in vitro kinase assay, Western blotting for phospho-specific proteins, pharmacologic inhibition, CCR5 knockout (CCR5Delta32) cells, and kinase-specific blocking peptide, we show for the first time that signaling through CCR5 in primary human macrophages is linked to the Src kinase Lyn [45].
• Reductions of cellularity and numbers of Ki-67(+), phospho-Kit(+), phospho-kinase domain-containing receptor-positive (phospho-KDR(+)), phospho-signal transducer and activator of transcription 5-positive (phospho-STAT5(+)), and phospho-Akt(+) cells were detected in bone marrow histology analysis [46].
• Here, we demonstrate that Akt phosphorylates the cell cycle inhibitory protein p21(Cip1) at Thr 145 in vitro and in intact cells as shown by in vitro kinase assays, site-directed mutagenesis, and phospho-peptide analysis [47].
• Immunohistochemistry and immunofluorescence analysis of cortical sections was used to validate the microarray results and to probe the activity of mTOR in cytomegalic neurons using phospho-specific antibodies directed against known mTOR targets [48].

References