Horace T. B. Ho

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Inhibition of cyclin-dependent kinases (CDKs) by Thr14/Tyr15 phosphorylation is critical for normal cell cycle progression and is a converging event for several cell cycle checkpoints. In this study, we compared the relative contribution of inhibitory phosphorylation for cyclin A/B1-CDC2 and cyclin A/E-CDK2 complexes. We found that inhibitory(More)
ING1b is a candidate tumor suppressor that can stimulate the transcriptional activity of p53 and inhibit cell proliferation. The molecular basis of how ING1b activates p53 function remains unclear. Here we show that ING1b could stimulate the activity of p53 by increasing the level and stability of the p53 protein. The stabilization and activation of p53 by(More)
Camptothecin and Adriamycin are clinically important inhibitors for topoisomerase (Topo) I and Topo II, respectively. The ataxia-telangiectasia mutated (ATM) product is essential for ionizing radiation-induced DNA damage responses, but the role of ATM in Topo poisons-induced checkpoints remains unresolved. We found that distinct mechanisms are involved in(More)
The choroid plexus (CP) is a highly vascularized tissue in the brain ventricles and acts as the blood-cerebrospinal fluid (CSF) barrier (BCSFB). A main function of the CP is to secrete CSF, which is accomplished by active transport of small ions and water from the blood side to the CSF side. The CP also supplies the brain with certain nutrients, hormones,(More)
Plasma membrane monoamine transporter (PMAT) is a novel polyspecific organic cation transporter that transports organic cations and the purine nucleoside, adenosine. PMAT is expressed in the kidney, but the specific localization and function of this transporter in renal cells are unclear. In this study, we developed a polyclonal antibody toward a 14-amino(More)
BACKGROUND Patients with autism spectrum disorder (ASD) may have low brain serotonin concentrations as reflected by the serotonin end-metabolite 5-hydroxyindolacetic acid (5HIAA) in cerebrospinal fluid (CSF). METHODS We sequenced the candidate genes SLC6A4 (SERT), SLC29A4 (PMAT), and GCHFR (GFRP), followed by whole exome analysis. RESULTS The known(More)
Plasma membrane monoamine transporter (PMAT) is a new polyspecific transporter that interacts with a wide range of structurally diverse organic cations. To map the physicochemical descriptors of cationic compounds that allow interaction with PMAT, we systematically analyzed the interactions between PMAT and three series of structural analogs of known(More)
Plasma membrane monoamine transporter (PMAT) is a polyspecific organic cation (OC) transporter that transports a variety of endogenous biogenic amines and xenobiotic cations. Previous radiotracer uptake studies showed that PMAT-mediated OC transport is sensitive to changes in membrane potential and extracellular pH, but the precise role of membrane(More)
Plasma membrane monoamine transporter (PMAT) is a polyspecific organic cation transporter in the solute carrier 29 (SLC29) family. Previous studies suggested that the major substrate recognition sites are located within transmembrane domains (TM) 1-6, and interaction of PMAT with organic cations may involve aromatic residues. In this study, we analyzed the(More)
246 words Introduction: 651 words Discussion: 1498 words Abbreviations: PMAT, plasma membrane monoamine transporter; SLC, solute carrier family; OCT, organic cation transporter; ENT, equilibrative nucleoside transporter; MPP, 1-methyl-4phenylpyridinium; DAT, dopamine transporter; SERT, serotonin transporter; CNS, central nervous system; MPTP,(More)