Author
Yehia Daaka
Other affiliations: Howard Hughes Medical Institute, Georgia Regents University, Duke University ...read more
Bio: Yehia Daaka is an academic researcher from University of Florida. The author has contributed to research in topics: G protein-coupled receptor & Prostate cancer. The author has an hindex of 46, co-authored 94 publications receiving 11222 citations. Previous affiliations of Yehia Daaka include Howard Hughes Medical Institute & Georgia Regents University.
Papers published on a yearly basis
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TL;DR: Data suggest that beta-arrestin binding, which terminates receptor-G protein coupling, also initiates a second wave of signal transduction in which the "desensitized" receptor functions as a critical structural component of a mitogenic signaling complex.
Abstract: The Ras-dependent activation of mitogen-activated protein (MAP) kinase pathways by many receptors coupled to heterotrimeric guanine nucleotide binding proteins (G proteins) requires the activation of Src family tyrosine kinases. Stimulation of beta2 adrenergic receptors resulted in the assembly of a protein complex containing activated c-Src and the receptor. Src recruitment was mediated by beta-arrestin, which functions as an adapter protein, binding both c-Src and the agonist-occupied receptor. beta-Arrestin 1 mutants, impaired either in c-Src binding or in the ability to target receptors to clathrin-coated pits, acted as dominant negative inhibitors of beta2 adrenergic receptor-mediated activation of the MAP kinases Erk1 and Erk2. These data suggest that beta-arrestin binding, which terminates receptor-G protein coupling, also initiates a second wave of signal transduction in which the "desensitized" receptor functions as a critical structural component of a mitogenic signaling complex.
1,451 citations
TL;DR: A mechanism previously shown to mediate uncoupling of the β2-adrenergic receptor from Gs and thus heterologous desensitization (PKA-mediated receptor phosphorylation), also serves to ‘switch’ coupling of this receptor fromGs to Gi and initiate a new set of signalling events.
Abstract: Many of the G-protein-coupled receptors for hormones that bind to the cell surface can signal to the interior of the cell through several different classes of G protein1,2,3,4. For example, although most of the actions of the prototype β2-adrenergic receptor are mediated through Gs proteins and the cyclic-AMP-dependent protein kinase (PKA) system5,6, β-adrenergic receptors can also couple to Gi proteins1,2. Here we investigate the mechanism that controls the specificity of this coupling. We show that in HEK293 cells, stimulation of mitogen-activated protein (MAP) kinase by the β2-adrenergic receptor is mediated by the βγ subunits of pertussis-toxin-sensitive G proteins through a pathway involving the non-receptor tyrosine kinase c-Src and the G protein Ras. Activation of this pathway by the β2-adrenergic receptor requires that the receptor be phosphorylated by PKA because it is blocked by H-89, an inhibitor of PKA. Additionally, a mutant of the receptor, which lacks the sites normally phosphorylated by PKA, can activate adenylyl cyclase5, the enzyme that generates cAMP, but not MAP kinase. Our results demonstrate that a mechanism previously shown to mediate uncoupling of the β2-adrenergic receptor from Gs and thus heterologous desensitization7 (PKA-mediated receptor phosphorylation), also serves to ‘switch’ coupling of this receptor from Gs to Gi and initiate a new set of signalling events.
1,284 citations
TL;DR: Three types of scaffolds for GPCR-directed complex assembly have been identified: transactivated receptor tyrosine kinases, integrin-based focal adhesions, and GPCRs themselves, and nonreceptor tyrosines play an important role in each case.
693 citations
TL;DR: These paradigms are inadequate to account for GPCR-mediated, Ras-dependent activation of the mitogen-activated protein (MAP) kinases Erk1 and -2, and β2-adrenergic receptor-mediated activation of MAP kinase is inhibited in HEK293 cells expressing dominant suppressor mutants of β-arrestin or dynamin.
546 citations
TL;DR: Results indicate that calcium-calmodulin plays a central role in the calcium-dependent regulation of tyrosine phosphorylation by G protein-coupled receptors in some systems, and indicate that in HEK-293 cells, the Gβγ subunit-mediated α2A-AR- and the Gαq/11-mediated βARK1ct-mediated Erk1/2 activation pathways converge at the level of phospholipase C.
465 citations
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TL;DR: Understanding of the complex signaling networks downstream from RTKs and how alterations in these networks are translated into cellular responses provides an important context for therapeutically countering the effects of pathogenic RTK mutations in cancer and other diseases.
7,056 citations
TL;DR: When epidermal growth factor and its relatives bind the ErbB family of receptors, they trigger a rich network of signalling pathways, culminating in responses ranging from cell division to death, motility to adhesion.
Abstract: When epidermal growth factor and its relatives bind the ErbB family of receptors, they trigger a rich network of signalling pathways, culminating in responses ranging from cell division to death, motility to adhesion. The network is often dysregulated in cancer and lends credence to the mantra that molecular understanding yields clinical benefit: over 25,000 women with breast cancer have now been treated with trastuzumab (Herceptin), a recombinant antibody designed to block the receptor ErbB2. Likewise, small-molecule enzyme inhibitors and monoclonal antibodies to ErbB1 are in advanced phases of clinical testing. What can this pathway teach us about translating basic science into clinical use?
6,462 citations
TL;DR: The development of brown adipose tissue with its characteristic protein, uncoupling protein-1 (UCP1), was probably determinative for the evolutionary success of mammals, as its thermogenesis enhances neonatal survival and allows for active life even in cold surroundings.
Abstract: Cannon, Barbara, and Jan Nedergaard. Brown Adipose Tissue: Function and Physiological Significance. Physiol Rev 84: 277–359, 2004; 10.1152/physrev.00015.2003.—The function of brown adipose tissue i...
5,470 citations
TL;DR: In this review particular emphasis is placed on the discrepancy between the concentrations ofadenosine, ADP, and ATP in the purine receptors of UDP and UTP.
Abstract: ### A. Overview
Extracellular purines (adenosine, ADP, and ATP) and pyrimidines (UDP and UTP) are important signaling molecules that mediate diverse biological effects via cell-surface receptors termed purine receptors. In this review particular emphasis is placed on the discrepancy between the
4,177 citations
TL;DR: Nonenzymatic mechanisms that impact MAP kinase functions and findings from gene disruption studies are highlighted and particular emphasis is on ERK1/2.
Abstract: Mitogen-activated protein (MAP) kinases comprise a family of ubiquitous proline-directed, protein-serine/threonine kinases, which participate in signal transduction pathways that control intracellular events including acute responses to hormones and major developmental changes in organisms. MAP kinases lie in protein kinase cascades. This review discusses the regulation and functions of mammalian MAP kinases. Nonenzymatic mechanisms that impact MAP kinase functions and findings from gene disruption studies are highlighted. Particular emphasis is on ERK1/2.
4,040 citations