Disease relevance of PHOSPHO1

• S6 phosphorylation in PMA-stimulated, serum-stimulated, and serum-starved Rous sarcoma virus-transformed CEF was analyzed by phospho amino acid analysis, two-dimensional polyacrylamide gel electrophoresis, limited proteolysis with V8 protease, and two-dimensional thin-layer electrophoresis of chymotryptic digests [1].

High impact information on PHOSPHO1

• Phospho amino acid analysis of talin from the infected cells confirmed the presence of phosphotyrosine, in addition to phosphoserine and phosphothreonine [2].
• Phospho amino acid analysis revealed phosphorylation at tyrosine residues, with no phosphorylation detectable at serine or threonine residues [3].
• Phosphoserine was the only phospho-amino acid detected in acid hydrolysates from phosphorylated S6 preparations [4].
• The amino acid phosphorylated in vitro was exclusively tyrosine in both cases, whereas p90 phosphorylated in vivo contained phosphoserine as a major phospho amino acid with traces of phosphotyrosine and phosphothreoine [5].
• To directly test for a role in proliferation, explants were immunostained with antibodies against phospho-histone H3 [6].

Biological context of PHOSPHO1

• In addition, PHOSPHO1 gene expression was determined in SaOS-2 and MG-63 osteoblast-like cells by RT-PCR [7].
• We have previously reported a novel gene (PHOSPHO1); a member of the large haloacid dehalogenase superfamily of hydrolases which has an active site indicative of a phosphatase [7].
• It is likely that 3X11A is a phosphatase, but its substrate specificity remains uncertain [8].
• In addition, by correlating expression patterns of Bmps, their receptors, and localization of phosphorylated R-Smad (phospho R-Smad) immunoreactivity, an indicator of BMP activation, we show that BMPs emanating from the otic epithelium influence chondrogenesis of the otic capsule including the cartilage surrounding the semicircular canals [9].
• A constant ratio of K (cat)/K (m), 4.3 x 10(4), found at different ethylene glycol concentrations, also supported the idea that the rate limiting step was the hydrolysis of the phospho enzyme intermediate [10].

Anatomical context of PHOSPHO1

• In 17-day-old embryonic calvaria, the osteoid present on the intramembranous and periosteal bone surfaces stained positively for PHOSPHO1 [7].
• Western analysis of chick growth plate cell lysate yielded bands (30.4 and 28.6 kD) corresponding to transcripts initiated at each of two possible initiation codons indicating the presence of alternative transcripts for PHOSPHO1 in growth cartilage [7].
• In diaphyseal cortical bone, immunohistochemistry localized PHOSPHO1 protein to the osteoid layer of the periosteum, forming surfaces of growing osteons, and newly formed osteocytes, whereas the endosteum and closed osteons were negative [7].
• This suggests that 3X11A participates in a biochemical pathway that is particularly active in differentiating chondrocytes [8].
• When immature cells of the anemia bone marrow are incubated in the presence of inorganic 32P and [3H]lysine and [3H]arginine, extensive 32P incorporation is found in the phospho species [11].

Associations of PHOSPHO1 with chemical compounds

• A substance apparently related to a compound consisting of phospho-peptide and ribulose-peptide in the yolk of chick embryos was isolated from acid soluble fractions of human semen by means of Dowex 1 (OH) form column chromatography [12].

Other interactions of PHOSPHO1

• However, a slight difference in peptides generated from phospho- and dephospho-forms of caldesmon is observed [13].

Analytical, diagnostic and therapeutic context of PHOSPHO1

• In addition to the radioactive technique, the extent of light chain phosphorylation was also measured by densitometry after separating the phospho and dephospho forms of the light chain with two-dimensional gel electrophoresis [14].
• Site-directed mutagenesis replacing the PKA phospho-acceptor amino acid residue impairs CNBP phosphorylation, suggesting that phosphorylation may not only exist in D. rerio but also in other vertebrates [15].

References