Abstract: The present invention provides a systematic and practical approach for the identification of candidate agents able to inhibit ubiquitin-mediated degradation of a cell-cycle regulatory protein, such as cyclins. One aspect of the present invention relates to a method for identifying an inhibitor of ubiquitin-mediated proteolysis of a cell-cycle regulatory protein by (i) providing a ubiquitin-conjugating system that includes the regulatory protein and ubiquitin under conditions which promote the ubiquitination of the target protein, and (ii) measuring the level of ubiquitination of the subject protein brought about by the system in the presence and absence of a candidate agent. A decrease in the level of ubiquitin conjugation is indicative of an inhibitory activity for the candidate agent.

Abstract: The present invention provides improvements in the expression cloning method for isolating novel cDNA clones. In particular, in the expression cloning method comprising the steps of preparing a cDNA library from a cell that expresses a desired protein; inserting the cDNA library into an expression vector; inserting the cDNA library into bacterial cells and culturing the bacterial cells to produce individual bacterial colonies; collecting pools of a predetermined number of individual bacterial colonies; isolating the cDNAs contained in the pools; expressing proteins encoded by the cDNAs; and detecting the desired protein, positive clones may be efficiently and cost-effectively obtained by collecting pools of about 100 individual bacterial colonies and expressing proteins encoded by the cDNAs in the pools in vitro.

Abstract: The present invention concerns a novel paracrine signaling assay.

Abstract: Disclosed herein are compositions and methods which are useful in the identification and isolation of components involved in transmembrane receptor-mediated signaling. Such components include the receptors themselves (e.g., tyrosine kinase receptors, cytokine receptors and tyrosine phosphatase receptors), as well as ligands which bind the receptors and modulators of the downstream intracellular catalytic event which characterizes receptor-mediated signalling.