Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transducin (T alpha and T beta gamma) is a GTP-binding protein involved in the visual transduction process in a rod outer segment. We have previously demonstrated that T beta gamma is a mixture composed of two components, T beta gamma-1 and T beta gamma-2, with distinctive gamma-subunits, T gamma-1 and T gamma-2, respectively (Fukada et al., 1989, J. Biol. Chem., 264, 5937-5943). To investigate the interaction between T alpha and the two components of T beta gamma, the effect of either T beta gamma-1 or T beta gamma-2 on the ADP-ribosylation of T alpha catalyzed by pertussis toxin (IAP) was examined. T beta gamma-2 stimulated the ADP-ribosylation of T alpha by IAP, while T beta gamma-1 displayed almost no enhancement of the ADP-ribosylation. Addition of T beta gamma-1 to the mixture of T alpha and T beta gamma-2 had no effect on the ADP-ribosylation of T alpha. These results indicate that T alpha and T beta gamma-2 form a complex that serves as a substrate of IAP in the ADP-ribosylation reaction, while T beta gamma-1 has a little affinity for T alpha. It was suggested that T gamma-2 is an essential subunit for T beta to interact with T alpha.
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PMID:A specific beta gamma-subunit of transducin stimulates ADP-ribosylation of the alpha-subunit by pertussis toxin. 232 68

A panel of monoclonal antibodies has been developed against the T alpha, T beta and T gamma subunits of bovine transducin. Two anti-T alpha antibodies from this panel (TF15 and TF16) and a third one (4A) against frog T alpha (Witt, P. L., Hamm, H. E., and Bownds, M. D. (1984) J. Gen. Physiol. 84, 251-263) were characterized. Each of these monoclonal antibodies recognizes a different region of T alpha and has a specific effect on the function of transducin. The binding of TF15 is reversibly enhanced by treating T alpha with either 1 M guanidinium chloride or, to a smaller extent, by the removal of bound guanine nucleotide. Its epitope is located in a 12-kDa tryptic fragment containing the binding site for the guanine moiety of GTP. Taken together, these results support previous observations that the conformation of T alpha is modulated by the occupancy of the guanine nucleotide binding site. In contrast to TF15, TF16 recognizes only the native form of T alpha. Its epitope resides within the central portion of the T alpha molecule. While T alpha-bound TF16 does not inhibit either pertussis toxin-catalyzed ADP-ribosylation, rhodopsin binding, or transducin subunit interaction, it blocks both the light-activated uptake of guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) and the GTP-dependent elution of transducin from photolyzed rhodopsin. These effects are unlikely to be caused by the occupation of the guanine nucleotide binding site by TF16 because this antibody quantitatively precipitates T alpha-GTP gamma S. We propose that bound TF16 locks T alpha in a conformation that prevents the entrance of guanine nucleotide and favors T beta gamma association. In contrast to TF16, the epitope of 4A was mapped to the amino-terminal region of T alpha. This monoclonal antibody blocks pertussis toxin-catalyzed ADP-ribosylation, GTP gamma S uptake, and T alpha-T beta gamma association. Moreover, the binding site for 4A becomes inaccessible when transducin binds to photolyzed rhodopsin. These results suggest that the inhibitory effects of 4A are due to a simultaneous steric blockage of both the interaction of T alpha with T beta gamma and their binding to photolyzed rhodopsin. The results obtained from these studies are correlated with the structure and function of T alpha.
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PMID:Characterization of transducin from bovine retinal rod outer segments. Use of monoclonal antibodies to probe the structure and function of the subunit. 312 13

We demonstrated that a primary exposure to the lymphocytosis promoting factor (LPF) of Bordetella pertussis-induced T cell colony formation. Colony formation was observed when mononuclear cells (MNC) were cultured at concentrations of more than 1 X 10(6)/ml, and reached a peak on day 8. However, the number of colonies generated with LPF was about one-third induced with phytohaemagglutinin (PHA). Removal of monocytes from MNC or T cells resulted in the failure of colony formation, but colony growth could be restored by the addition of monocytes or B enriched cells, indicating that they were required for the optimal colony growth induced by LPF. In the absence of accessory cells, optimal colony growth from monocyte depleted T cells could be obtained when an appropriate concentration of phorbol myristate acetate (PMA) or interleukin-2 (IL-2) was added in the cultures with LPF. PMA did not enhance LPF-induced colony formation in the cultures containing a sufficient amount of exogeneous IL-2. These findings suggest that IL-2 is essential to LPF-induced colony formation. Surface marker analysis showed that most of LPF-induced colony cells were T cells. The percentages of T4+ and T gamma cells of LPF-induced colony cells were more, and T8+ cells less, than those of PHA-induced colony cells. Ia1, T9 and Tac antigens were detected on many colony cells induced by LPF or PHA. These results indicate that the phenotype of LPF-induced colony cells differs from those of PHA, but the sequential antigen expression on lymphocytes triggered by IL-2 might be similar in both LPF- and PHA-induced colony formation.
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PMID:LPF-induced T cell colony formation: effect of PMA and interleukin-2, and surface marker analysis. 387 28

We studied the effect of lymphocytosis promoting factor (LPF), derived from the supernatant fluid of a culture of phase I Bordetella pertussis strain Tohama, on human lymphocyte proliferation. LPF was a potent mitogen for human mononuclear cells, specifically T cells. LPF failed to induce cytoplasmic immunoglobulin production by B cells. Removal of the monocytes from the T cell fraction diminished responses to LPF, but the response could be restored completely by the addition of 5.0% monocytes. These results suggest that LPF-induced cell proliferation is at least partially dependent on monocytes. In contrast to PHA, LPF stimulated T gamma cells to a greater extent than non-T gamma cells, but the magnitude of the T gamma or non-T gamma cell response was less than that of T cells, indicating that synergistic interactions between T gamma and non-T gamma cells are required for maximal response.
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PMID:The mitogenic effect of the lymphocytosis promoting factor from Bordetella pertussis on human T gamma and non-T gamma cells. 609 59

Transducin serves as a mediator between the receptor protein, rhodopsin, and the effector protein, cGMP phosphodiesterase, in the visual process. Transducin is a protein composed of three polypeptides: T alpha, T beta, and T gamma, and acts as two functional units, the alpha-subunit and the beta gamma-complex. In the present study, I describe an efficient and fast method of purifying T alpha and T beta gamma using chromatography on a blue agarose column connected in tandem with an omega-amino octylagarose column. The recombination of T alpha and T beta gamma reconstitutes the functional heterotrimeric holoprotein, as demonstrated by the recovery of three native properties of transducin: 1) its capacity to exchange guanine nucleotide, 2) its GTP hydrolytic activity, and 3) the ADP-ribosylation of T alpha catalysed by pertussis toxin.
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PMID:Improved purification of transducin subunits from bovine retinal rod outer segments. 925 60