Interaction of neuronal nitric oxide synthase with alpha(1)-adrenergic receptor subtypes in transfected HEK-293 cells

BACKGROUND: The C-terminal four amino acids (GEEV) of human α(1A)-adrenergic receptors (ARs) have been reported to interact with the PDZ domain of neuronal nitric oxide synthase (nNOS) in a yeast two-hybrid system. The other two α(1)-AR subtypes have no sequence homology in this region, raising the possibility of subtype-specific protein-protein interactions. RESULTS: We used co-immunoprecipitation and functional approaches with epitope-tagged α(1)-ARs to examine this interaction and the importance of the C-terminal tail. Following co-transfection of HEK-293 cells with hexahistidine/Flag (HF)-tagged α(1A)-ARs and nNOS, membranes were solubilized and immunoprecipitated with anti-FLAG affinity resin or anti-nNOS antibodies. Immunoprecipitation of HFα(1A)-ARs resulted in co-immunoprecipitation of nNOS and vice versa, confirming that these proteins interact. However, nNOS also co-immunoprecipitated with HFα(1B)- and HFα(1D)-ARs, suggesting that the interaction is not specific to the α(1A) subtype. In addition, nNOS co-immunoprecipitated with each of the three HFα(1)-AR subtypes which had been C-terminally truncated, suggesting that this interaction does not require the C-tails; and with Flag-tagged β(1)- and β(2)-ARs. Treatment of PC12 cells expressing HFα(1A)-ARs with an inhibitor of nitric oxide formation did not alter norepinephrine-mediated activation of mitogen activated protein kinases, suggesting nNOS is not involved in this response. CONCLUSIONS: These results show that nNOS does interact with full-length α(1A)-ARs, but that this interaction is not subtype-specific and does not require the C-terminal tail, raising questions about its functional significance

A follow-up study of the life styles of former honors and non-honors students in the college of home economics

Call number: LD2668 .T4 1967 M5968Master of Scienc

A telecommunications aid for the deaf : an algorithm for extracting readable English text from Touch-Tone® keystroke sequences

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERINGBibliography: leaves 69-74.by Scott L. Minneman.M.S

Protein logic: a statistical mechanical study of signal integration at the single-molecule level

Information processing and decision making is based upon logic operations, which in cellular networks has been well characterized at the level of transcription. In recent years however, both experimentalists and theorists have begun to appreciate that cellular decision making can also be performed at the level of a single protein, giving rise to the notion of protein logic. Here we systematically explore protein logic using a well known statistical mechanical model. As an example system, we focus on receptors which bind either one or two ligands, and their associated dimers. Notably, we find that a single heterodimer can realize any of the 16 possible logic gates, including the XOR gate, by variation of biochemical parameters. We then introduce the novel idea that a set of receptors with fixed parameters can encode functionally unique logic gates simply by forming different dimeric combinations. An exhaustive search reveals that the simplest set of receptors (two single-ligand receptors and one double-ligand receptor) can realize several different groups of three unique gates, a result for which the parametric analysis of single receptors and dimers provides a clear interpretation. Both results underscore the surprising functional freedom readily available to cells at the single-protein level.Comment: 19 pages, 4 figures and 9 pages S

Investigation of the impact of water absorption on retinal OCT imaging in the 1060 nm range

Recently, the wavelength range around 1060 nm has become attractive for retinal imaging with optical coherence tomography (OCT), promising deep penetration into the retina and the choroid. The adjacent water absorption bands limit the useful bandwidth of broadband light sources, but until now, the actual limitation has not been quantified in detail. We have numerically investigated the impact of water absorption on the axial resolution and signal amplitude for a wide range of light source bandwidths and center wavelengths. Furthermore, we have calculated the sensitivity penalty for maintaining the optimal resolution by spectral shaping. As our results show, with currently available semiconductor-based light sources with up to 100–120 nm bandwidth centered close to 1060 nm, the resolution degradation caused by the water absorption spectrum is smaller than 10%, and it can be compensated by spectral shaping with negligible sensitivity penalty. With increasing bandwidth, the resolution degradation and signal attenuation become stronger, and the optimal operating point shifts towards shorter wavelengths. These relationships are important to take into account for the development of new broadband light sources for OCT