PRAS40 (proline-rich Akt substrate 40 kD) associates with mammalian target of rapamycin complex 1(mTORC1), serine 183 site (Ser183) of PRAS40 can be phosphorylated by mTORC1. To prepare the phosphorylated PRAS40 (Ser183) antibody, We chosen 10-amino acid including Ser183 as antigen peptide through antigenicity and hydrophobicity analysis, hinged on keyhole limpet hemocyanin (KLH), and used the KLH-peptide to immunize rabbits. After antibody serum titer detection by enzyme linked immunosorbent assay (ELISA), the antibody was purified with rProtein A sepharose fast flow and dephosphorylated antigen membrane. The antibody titrate reached 1:10 000 after purification and its special property was enhanced with absorption treatment of dephosphorylated antigen membrane. In addition, we used rabbit anti-PRAS40 antibody and the phosphorylated PRAS40 (Ser183) antibody to detect PRAS40 expression in several cell lines, including the normal cells HL7702, HEK293, tumor cells HepG2, A549 and S180. There were no quite difference among these cells; otherwise, we observed the decreased phosphorylation level of Ser183 after amino acid withdrawal treatment. Therefore, the polyclonal phosphorylated PRAS40 (Ser183) antibody was specific to PRAS40 (Ser183) site and could be used for the function study of PRAS40.
Adaptor Proteins, Signal Transducing ; Animals ; Antibodies ; analysis ; Cell Line, Tumor ; Humans ; Male ; Mechanistic Target of Rapamycin Complex 1 ; Multiprotein Complexes ; Phosphoproteins ; chemistry ; immunology ; Proteins ; genetics ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Rabbits ; Serine ; metabolism ; TOR Serine-Threonine Kinases

Successful preemptive therapy for cytomegalovirus (CMV) infection in transplant patients depends on the availability of sensitive, specific, and timely diagnostic tests for CMV infection. Although the pp65 antigenemia assay has been widely used for this purpose, real-time quantification of CMV DNA has recently been recognized as an alternative diagnostic approach. However, the guidelines for antiviral therapy based on real-time quantitative polymerase chain reaction (RQ-PCR) have yet to be established. From November 2004 to March 2005, a total of 555 whole blood samples from 131 hematopoietic stem cell transplant (HSCT) recipients were prospectively collected. RQ-PCR was conducted using an Artus(R) CMV LC PCR kit (QIAGEN). Both qualitative and quantitative correlations were drawn between the two methods. Exposure to the antiviral agent influenced the results of the two assays. Additionally, the discrepancy was observed at low levels of antigenemia and CMV DNA load. Via ROC curve analysis, the tentative cutoff value for preemptive therapy was determined to be approximately 2x10(4) copies/mL (sensitivity, 80.0%; specificity, 50.0%) in the high risk patients, and approximately 3x10(4) copies/mL (sensitivity, 90.0%; specificity, 70.0%) in the patients at low risk for CMV disease. Further study to validate the optimal cutoff value for the initiation of preemptive therapy is currently underway.
Adolescent ; Adult ; Child ; Child, Preschool ; Cytomegalovirus/genetics/*isolation & purification ; Cytomegalovirus Infections/*diagnosis/therapy ; DNA, Viral/*blood ; Female ; *Hematopoietic Stem Cell Transplantation ; Humans ; Infant ; Male ; Middle Aged ; Phosphoproteins/analysis/immunology ; Polymerase Chain Reaction/*methods ; ROC Curve ; Reagent Kits, Diagnostic ; Sensitivity and Specificity ; Viral Matrix Proteins/analysis/immunology