Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The regulator of T-cell proliferation prothymosin alpha, is a protein with a relative molecular mass of 12 KDa as calculated from its amino acid sequence. This immunoregulator exhibits anomalous behaviour on gel-filtration and SDS-PAGE electrophoresis appearing as oligomers which are 5 or 2 fold larger than the corresponding polypeptide. These results suggest that a dimeric form of prothymosin alpha is stable to dissociation by SDS and reduction by beta-mercapto ethanol.
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PMID:On the anomalous behaviour on gel-filtration and SDS-electrophoresis of prothymosin-alpha. 129 Apr 67

A sensitive and specific microELISA assay is described for the immunoactive polypeptide parathymosin. Antibodies against a synthetic peptide corresponding to the rat parathymosin sequence 5-30 were raised in rabbits immunised with this peptide conjugated to keyhole limpet hemocyanin (KLH). The useful range of the assay was 0.25-30 pmol (3-330 ng) of parathymosin and the assay was specific. The related immunoactive polypeptides prothymosin alpha or thymosin alpha 1 showed no cross-reactivity. In spiking experiments the recovery of the assay was found to be greater than 92% at all concentrations tested. The intra-assay variation was 17%, whereas the inter-assay variation was 26%. Using this assay the highest concentration of parathymosin was found in porcine liver, followed by kidney, lung, thymus and spleen. This assay compares favorably with one microELISA and two RIA methods already published, in that it is more sensitive by at least an order of magnitude, and it is simpler and quicker.
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PMID:A sensitive and specific competition microELISA for the immunoactive polypeptide parathymosin and detection of this peptide in porcine tissues. 137 27

Prothymosin alpha (ProT alpha) is a 12.5 kDa acidic polypeptide that is considered to have a nuclear function related to cell proliferation. Inspection of its amino acid sequence revealed the presence of sequences that may serve as targets for phosphorylation by casein kinase-2 (CK-2). ProT alpha isolated from calf thymocytes was phosphorylated in vitro by CK-2. The phosphorylation sites are Ser and Thr residues located among the first 14 amino acid residues in the ProT alpha sequence. Another site that is theoretically suitable for phosphorylation by CK-2, at the C-terminus of the polypeptide, is not, in fact, phosphorylated. Thymosin alpha 1 (T alpha 1), a peptide whose sequence corresponds to the first 28 amino acids of ProT alpha, is also phosphorylated by CK-2 at the same phosphorylation sites as ProT alpha. In cultured splenic lymphocytes ProT alpha was phosphorylated at Thr residues located at positions 7, 12 and/or 13. Based on these observations we conclude that CK-2, or another cellular kinase with similar sequence specificity, is responsible for phosphorylation of ProT alpha in vivo.
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PMID:Prothymosin alpha is phosphorylated by casein kinase-2. 142 45

Prothymosin alpha, a polypeptide of 109 to 111 amino acid residues, contains the entire thymosin alpha 1 sequence (residues 1-28) at its amino terminal. Human peripheral blood monocytes incubated with prothymosin alpha release thymosin alpha 1 in the culture supernatants. In addition total RNA is found to increase. The production of thymosin alpha 1 involves de novo protein synthesis as shown by the kinetics of this release and its inhibition by actinomycin D and cycloheximide. Thymosin alpha 1 release, possibly in association with HLA-DR, stimulates the proliferation of the T cell population.
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PMID:Appearance of thymosin alpha 1 in supernatants of monocytes incubated with prothymosin alpha. 153 80

Prothymosin alpha (ProT alpha) is an acidic polypeptide with potentiating effects on HLA-DR-restricted in vitro cellular immune response systems such as T cell proliferative responses to soluble proteins and cellular auto- or alloantigens. Experiments were performed to investigate the effect of ProT alpha on MHC class II Ag expression in human monocytes, murine splenocytes, and tumor cell lines at both protein and molecular levels. RIA and immunofluorescence analysis revealed that ProT alpha enhances HLA-DR surface Ag expression whereas Northern blot analysis demonstrated that ProT alpha causes significant accumulation of MHC class II mRNA. The enhancing effect of ProT alpha was demonstrated convincingly using precultured human peripheral monocytes, which are known to express decreased amounts of surface HLA-DR Ag, and HLA-DR-positive human cell lines. Moreover, ProT alpha was shown to induce HLA-DR Ag expression in a priori HLA-DR-negative tumor cells. Furthermore, ProT alpha was shown to be active in vivo. Splenocytes from mice pretreated with ProT alpha expressed more surface Ilpha Ag and contained more I alpha-specific mRNA. These findings suggest that ProT alpha may be important in the regulation of the immune response by enhancing MHC class II Ag expression in APC.
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PMID:Prothymosin alpha enhances human and murine MHC class II surface antigen expression and messenger RNA accumulation. 154 15

Failure to detect thymosin alpha 1 (T alpha 1) in tissue extracts prepared by procedures that prevent proteolytic activity has hitherto supported the suggestion that T alpha 1 is not a natural peptide, but the product of uncontrolled proteolysis of prothymosin alpha (ProT alpha), a polypeptide that includes T alpha 1 at its NH2 terminus. In this work, purification by isoelectric focusing of a product with the same isoelectric point as synthetic T alpha 1, and its further characterization, demonstrated that T alpha 1 is present as a native peptide in calf thymus and in several lymphoid and non-lymphoid rat tissues. T alpha 1 shows abnormal chromatographic behaviour which appears to be due to association with other components in tissue extracts. In all the tissues studied, T alpha 1 was present in higher concentration than ProT alpha (80-183 and 44-123 micrograms per gram of tissue, respectively). The ProT alpha/T alpha 1 ratio did not change when no measures were taken to prevent proteolysis during tissue homogenization.
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PMID:Thymosin alpha 1 is a native peptide in several tissues. 155 40

Goat prothymosin alpha, a highly acidic polypeptide of pI3.5, 109 amino acid residues, has been isolated from lymphoid and non-lymphoid tissues of young female goats. Unlike rat, murine and porcine prothymosins alpha, goat prothymosin alpha appears at a higher concentration in the spleen compared with the thymus. The sequence of segments of the polypeptide involving known mutations has been determined, by automatic sequencing of its tryptic peptide fragments. The acidic amino acid-rich segment in the middle of the molecule, including residues 49-83, has not been sequenced. Goat prothymosin alpha closely resembles bovine prothymosin alpha, with only one substitution, proline for alanine at position 85. It also resembles human prothymosin alpha, with only three substitutions. It differs more significantly from rat and murine prothymosins alpha, by two deletions and three substitutions. The results show the highly conserved nature of the molecule, with substitutions at given positions only.
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PMID:Isolation and partial sequence of goat spleen prothymosin alpha. 177 Sep 47

There is a large body of evidence for the role of thymosin peptides in immunogenesis and immunity. In this paper we report on the influence of prothymosin alpha 1 (ProT-alpha 1), a hormone-like peptide derived from the calf thymus, on humoral and cellular immune reactions in the rat. Young adults received intraperitoneal injections of ProT-alpha 1 in the periods before and after immunization with cellular and soluble antigens. ProT-alpha-treatment produced a dose-dependent increase of both humoral and cell-mediated immune responses. The thymus weight increased but not that of spleen. Treatment of nonimmunized rats with this polypeptide significantly elevated the number of CD4+ and decreased the number of CD8+ cells in the peripheral blood. The results suggest a potent immunostimulatory activity of ProT-alpha 1 and imply direct action of this polypeptide on T lymphocytes.
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PMID:In vivo effect of prothymosin-alpha 1 on humoral and cell-mediated immune responses in the young rat. 183 89

Rat prothymosin alpha fragment 29-111, an 83-residue polypeptide corresponding to desthymosin alpha 1-prothymosin alpha, has been synthesized by a solid-phase method. Hydrogen fluoride was used to deprotect and cleave the peptide from the resin. The crude product was purified by gel-filtration, ion-exchange chromatography and high-performance liquid chromatography. A 3.2-mg sample of a ca. 96% pure peptide was finally obtained. The overall yield of the synthesis was less than 1%. An increase of E-rosette-forming lymphocytes was obtained after incubation of peripheral blood from uremic patients with the synthetic prothymosin alpha fragment 29-111. The restoring effect of the synthetic prothymosin alpha fragment 29-111 was greater than that of our synthetic thymosin alpha 1.
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PMID:Solid-phase synthesis of biologically active fragment 29-111 of rat prothymosin alpha. 188 31

We have purified to homogeneity a 15-kDa perchloric acid (PCA)-soluble protein from rat thymus nuclei. This highly acidic protein showed a Mr of ca. 30 kDa in acetic acid/urea gels, probably due to oligomer formation. Sequence analysis of internal tryptic and thermolytic peptides revealed that the purified protein is, in fact, prothymosin alpha, a very hydrophilic polypeptide, which has been previously classified as a thymic or immunomodulating hormone. We found that prothymosin alpha is a rather abundant nuclear protein in rat thymus; its concentration is comparable to that of a well-characterized nonhistone protein HMG-14. The subcellular localization and physicochemical properties of prothymosin alpha suggest that its function is related to those of other long polyacidic regions containing nuclear proteins.
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PMID:Identification of a low-Mr acidic nuclear protein as prothymosin alpha. 226 62


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