Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0220723 (PCA)
 4,687 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The transporter associated with antigen presentation (TAP) is an ATP-binding cassette (ABC) protein which transports peptides for presentation to the immune system. TAP is composed of two half transporters, TAP1 (ABCB2) and TAP2 (ABCB3), which heterodimerize to function. In humans, the TAP family consists of TAP1, TAP2, and TAPL (ABCB9). While the TAP1-TAP2 complex is well characterized, TAPL's dimerization state and function are unknown. To identify interactions within the human TAP family, we adapted the dihydrofolate reductase protein-fragment complementation assay (DHFR PCA) to half ABC transporters. This assay has been shown to be suitable for the study of membrane-bound proteins in vivo [Remy, I., Wilson, I. A., and Michnick, S. W. (1999) Science 283, 990-993]. With this method, in vivo TAP1-TAP2 heterodimerization was confirmed, no homodimerizations were detected with TAP1 or TAP2, and TAPL did not show any interaction with TAP1 or TAP2. However, we found strong evidence that TAPL forms homodimers. These results provide evidence of a novel homomeric TAPL interaction and demonstrate that the DHFR PCA will be of general utility in studies of half ABC transporter interactions in vivo.
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PMID:Detection of TAP family dimerizations by an in vivo assay in mammalian cells. 1551 76

One of the most important challenges in systems biology is to understand how cells respond to genetic and environmental perturbations. Here we show that the yeast DHFR-PCA, coupled with high-resolution growth profiling (DHFR-qPCA), is a straightforward assay to study the modulation of protein-protein interactions (PPIs) in vivo as a response to genetic, metabolic and drug perturbations. Using the canonical Protein Kinase A (PKA) pathway as a test system, we show that changes in PKA activity can be measured in living cells as a modulation of the interaction between its regulatory (Bcy1) and catalytic (Tpk1 and Tpk2) subunits in response to changes in carbon metabolism, caffeine and methyl methanesulfonate (MMS) treatments and to modifications in the dosage of its enzymatic regulators, the phosphodiesterases. Our results show that the DHFR-qPCA is easily implementable and amenable to high-throughput. The DHFR-qPCA will pave the way to the study of the effects of drug, genetic and environmental perturbations on in vivo PPI networks, thus allowing the exploration of new spaces of the eukaryotic interactome.
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PMID:qPCA: a scalable assay to measure the perturbation of protein-protein interactions in living cells. 2309 92

Understanding the function of cellular systems requires describing how proteins assemble with each other into transient and stable complexes and to determine their spatial relationships. Among the tools available to perform these analyses on a large scale is Protein-fragment Complementation Assay based on the dihydrofolate reductase (DHFR PCA). Here we test how longer linkers between the fusion proteins and the reporter fragments affect the performance of this assay. We investigate the architecture of the RNA polymerases, the proteasome and the conserved oligomeric Golgi (COG) complexes in living cells and performed large-scale screens with these extended linkers. We show that longer linkers significantly improve the detection of protein-protein interactions and allow to measure interactions further in space than the standard ones. We identify new interactions, for instance between the retromer complex and proteins related to autophagy and endocytosis. Longer linkers thus contribute an enhanced additional tool to the existing toolsets for the detection and measurements of protein-protein interactions and protein proximity in living cells.
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PMID:Extended Linkers Improve the Detection of Protein-protein Interactions (PPIs) by Dihydrofolate Reductase Protein-fragment Complementation Assay (DHFR PCA) in Living Cells. 2949 12