A5028159080- Receptor Mechanisms and Signaling
- Protein Kinase Regulation and GTPase Signaling
- Prostate Cancer Treatment and Research
- Macrophage Migration Inhibitory Factor
- Neuropeptides and Animal Physiology
- Hormonal and reproductive studies
- GDF15 and Related Biomarkers
- Estrogen and related hormone effects
- Cell Adhesion Molecules Research
- Immune cells in cancer
- Cellular transport and secretion
- PI3K/AKT/mTOR signaling in cancer
- Mass Spectrometry Techniques and Applications
- Cannabis and Cannabinoid Research
- Immune Cell Function and Interaction
- Melanoma and MAPK Pathways
- Inflammatory mediators and NSAID effects
- Nitric Oxide and Endothelin Effects
- Protein Degradation and Inhibitors
- Mechanisms of cancer metastasis
- Ubiquitin and proteasome pathways
- Eicosanoids and Hypertension Pharmacology
- Coagulation, Bradykinin, Polyphosphates, and Angioedema
- Sphingolipid Metabolism and Signaling
- Cellular Mechanics and Interactions
Florida College
2012-2023
University of Florida
2013-2023
University of Florida Health
2018-2023
UF Health Cancer Center
2023
Augusta University Health
2011
The Prostate Centre
2011
Augusta University
2006-2011
University of California, San Francisco
2011
Istituto Superiore di Sanità
2008
Duke Medical Center
1997-2006
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 Src family tyrosine kinases. Stimulation β 2 adrenergic resulted in assembly a complex containing activated c-Src and receptor. recruitment was mediated β-arrestin, which functions as an adapter protein, both agonist-occupied β-Arrestin 1 mutants, impaired either or ability target clathrin-coated pits, acted...
The classical paradigm for G protein-coupled receptor (GPCR) signal transduction involves the agonist-dependent interaction of GPCRs with heterotrimeric proteins at plasma membrane and subsequent generation, by membrane-localized effectors, soluble second messengers or ion currents. Termination GPCR signals follows kinase (GRK)- beta-arrestin-mediated uncoupling internalization. Here we show that these paradigms are inadequate to account GPCR-mediated, Ras-dependent activation...
Many receptors that couple to heterotrimeric guanine-nucleotide binding proteins (G proteins) have been shown mediate rapid activation of the mitogen-activated protein kinases Erk1 and Erk2. In different cell types, signaling pathways employed appear be a function available repertoire receptors, G proteins, effectors. HEK-293 cells, stimulation either α1B- or α2A-adrenergic (ARs) leads 5–10-fold increases in Erk1/2 phosphorylation. Phosphorylation response α2A-AR is effectively attenuated by...
Both the α and βγ subunits of heterotrimeric guanine nucleotide–binding proteins (G proteins) communicate signals from receptors to effectors. Gβγ can regulate a diverse array effectors, including ion channels enzymes. Gα bound diphosphate (Gα-GDP) inhibit signal transduction through subunits, suggesting common interface on for binding effector interaction. The molecular basis interaction with effectors was characterized by mutational analysis Gβ residues that make contact Gα-GDP. Analysis...
Many G protein-coupled receptors (GPCRs) activate MAP kinases by stimulating tyrosine kinase signaling cascades. In some systems, GPCRs stimulate phosphorylation inducing the "transactivation" of a receptor (RTK). The mechanisms underlying GPCR-induced RTK transactivation have not been clearly defined. Here we report that GPCR activation mimics growth factor-mediated stimulation epidermal factor (EGFR) with respect to many facets function. beta(2)-Adrenergic (beta(2)AR) COS-7 cells induces...
G protein-coupled receptor kinases phosphorylate the agonist occupied conformation of receptors in plasma membrane, leading to their desensitization. Receptor resensitization requires dephosphorylation, a process which is mediated by and vesicular membrane-associated form PP-2A. We present evidence that, like phosphorylation, dephosphorylation tightly regulated, requiring specific induced acidification. In vitro, spontaneous phosphorylated observed only at acidic pH. Furthermore, intact...
Some forms of G protein-coupled receptor signaling, such as activation mitogen-activated protein kinase cascade well resensitization receptors after hormone-induced desensitization, require internalization via dynamin-dependent clathrin-coated pit mechanisms. Here we demonstrate that β2-adrenergic (β2-ARs) leads to c-Src-mediated tyrosine phosphorylation dynamin, which is required for internalization. Two residues, Tyr231 and Tyr597, are identified the major sites. Mutation these residues...
G protein-coupled receptors (GPCRs) initiate Ras-dependent activation of the Erk 1/2 mitogen-activated protein kinase cascade by stimulating recruitment Ras guanine nucleotide exchange factors to plasma membrane. Both integrin-based focal adhesion complexes and receptor tyrosine kinases have been proposed as scaffolds upon which GPCR-induced complex may assemble. Using specific inhibitors assembly activation, we determined relative contribution each following stimulation endogenous GPCRs in...
beta-Arrestins serve a dual regulatory role in the life cycle of G protein-coupled receptors such as beta2-adrenergic receptor. First, they mediate rapid desensitization by binding to receptor kinase-phosphorylated receptors. Second, target for internalization into endosomal vesicles, wherein dephosphorylation and resensitization occur. Here we report that phosphorylation carboxyl-terminal serine (Ser-412) beta-arrestin1 regulates its endocytotic but not function. Cytoplasmic is...
The Ras-dependent activation of Erk kinases by G protein-coupled receptors (GPCRs) is thought to involve tyrosine phosphorylation docking proteins that serve as scaffolds for the plasma membrane recruitment Ras guanine nucleotide exchange factors, such Grb2-mSos complex. We have investigated role two GPCR-regulated phosphoproteins, p125FAK (FAK) and Shc, in endogenously expressed GPCRs Rat 1a fibroblasts. Several lines evidence suggest FAK Shc are independently regulated. lysophosphatidic...
Acting through a number of distinct pathways, many G protein-coupled receptors (GPCRs) activate the extracellular signal-regulated kinase (ERK)/mitogen-activated protein (MAPK) cascade. Recently, it has been shown that in some cases, clathrin-mediated endocytosis is required for GPCR activation ERK/MAPK cascade, whereas others not. Accordingly, we compared ERK mediated by does not undergo agonist-stimulated endocytosis, alpha(2A) adrenergic receptor (alpha(2A) AR), with beta(2) (beta(2)...
The G protein-coupled receptor (GPCR) kinases (GRKs) phosphorylate and desensitize agonist-occupied GPCRs. GRK2-mediated phosphorylation is preceded by the agonist-dependent membrane association of this enzyme. Previous in vitro studies with purified proteins have suggested that translocation may be mediated recruitment GRK2 to plasma its interaction free βγ subunits heterotrimeric (Gβγ). Here we demonstrate mechanism operates intact cells specificity imparted selective discrete pools Gβγ...
The GTPase dynamin regulates endocytic vesicle budding from the plasma membrane, but molecular mechanisms involved remain incompletely understood. We report that dynamin, which interacts with NO synthase, is S -nitrosylated at a single cysteine residue (C607) after stimulation of β 2 adrenergic receptor. -nitrosylation increases self-assembly and activity facilitates its redistribution to membrane. A mutant protein bearing C607A substitution does not self-assemble properly or increase...
Although the prognosis for patients with early-stage breast cancer has improved, therapeutic options locally advanced and metastatic disease are limited. To improve treatment of these patients, molecular mechanisms underlying invasion metastasis must be understood. In this study, we report that signaling through G12 family heterotrimeric G proteins (Galpha12 Galpha13) promotes cell invasion. Moreover, demonstrate inhibition reduces dissemination cells in vivo. Finally, expression Galpha12 is...
Many human cancers express elevated levels of cyclooxygenase-2 (COX-2), an enzyme responsible for the biosynthesis prostaglandins. Available clinical data establish protective effect COX-2 inhibition on cancer progression. However, despite these encouraging outcomes, appearance unwanted side effects remains a major hurdle general application inhibitors as effective drugs. Hence, better understanding molecular signals downstream is needed elucidation drug targets that may improve therapy....
Endocytosis of ligand-activated receptors requires dynamin-mediated GTP hydrolysis, which is regulated by dynamin self-assembly. Here, we demonstrate that phosphorylation I c-Src induces its self-assembly and increases GTPase activity. Electron microscopic analyses reveal tyrosine-phosphorylated spontaneously self-assembles into large stacks rings. Tyrosine 597 was identified as being phosphorylated both <i>in vitro</i> in cultured cells following epidermal growth factor receptor...
Many studies have suggested a role for the members of G12 family heterotrimeric G proteins (Gα12 and Gα13) in oncogenesis tumor cell growth. However, few examined signaling actual human cancers. In this study, we prostate cancer. We found that expression is significantly elevated Interestingly, activated forms Gα12 or Gα13 PC3 DU145 cancer lines did not promote Instead, these induced invasion through activation RhoA proteins. Furthermore, inhibition by RGS domain p115-Rho-specific guanine...