Madan Mohan Kwatra

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Homologous or agonist-specific desensitization of beta 2-adrenergic receptors (beta 2AR) is mediated by the beta-adrenergic receptor kinase (beta ARK) which specifically phosphorylates the agonist-occupied form of the receptor. However, the capacity of beta ARK-phosphorylated beta 2AR to stimulate Gs in a reconstituted system is only minimally impaired.(More)
The rate and extent of the agonist-dependent phosphorylation of beta 2-adrenergic receptors and rhodopsin by beta-adrenergic receptor kinase (beta ARK) are markedly enhanced on addition of G protein beta gamma subunits. With a model peptide substrate it was demonstrated that direct activation of the kinase could not account for this effect. G protein beta(More)
An aromatic residue, tyrosine 326 in the prototypical human beta 2-adrenergic receptor, exists in a highly conserved sequence motif in virtually all members of the G protein-coupled receptor family. The potential role of this conserved aromatic amino acid residue in the cellular processes of sequestration (a rapid internalization of the surface receptor)(More)
BACKGROUND Postoperative delirium, a common complication in the elderly, can occur following any type of surgery and is associated with increased morbidity and mortality; it may also be associated with subsequent cognitive problems. Effective therapy for postoperative delirium remains elusive because the causative factors of delirium are likely multiple and(More)
We have investigated human gliomas that amplify and rearrange the epidermal growth factor receptor gene, with generation of an in-frame deletion mutation of 802 nucleotides in the external domain. This in-frame deletion mutation generates a local amino acid sequence at the fusion junction of what normally were distant polypeptide sequences in the intact(More)
Substance P receptor (SPR), which plays a key role in pain transmission, is known to undergo rapid agonist-dependent desensitization and internalization. The present study shows that human SPR undergoes agonist-dependent phosphorylation in intact cells. Immunoprecipitation of SPR from 32Pi-labeled Chinese hamster ovary cells stably expressing human SPR(More)
Previous studies have shown that neurokinin 1 receptor (NK1R) occurs naturally in human glioblastomas and its stimulation causes cell proliferation. In the present study we show that stimulation of NK1R in human U373 glioblastoma cells by substance P increases Akt phosphorylation by 2.5-fold, with an EC(50) of 57 nM. Blockade of NK1R lowers basal(More)
Substance P receptor (SPR) stably expressed in Chinese hamster ovary (CHO) cells stimulates at least three second messenger systems including phosphoinositide hydrolysis, cyclic AMP (cAMP) formation, and arachidonic acid release. Whether these second messenger systems are activated via single or multiple G proteins is not known. Therefore, in the present(More)
BACKGROUND Patients with cardiac valve disease (CVD) frequently have congestive heart failure (CHF) and chronic myocardial beta-adrenergic receptor (beta AR) desensitization. Cardiac surgery requiring cardiopulmonary bypass (CPB) is associated with increased plasma catecholamine concentrations, which might worsen myocardial beta AR function. We therefore(More)