Ca(2+)/calmodulin-dependent protein kinase II interacts with group I metabotropic glutamate and facilitates receptor endocytosis and ERK1/2 signaling: role of β-amyloid.

Background: Agonist stimulation of Group I metabotropic glutamate receptors (mGluRs) initiates their coupling to the heterotrimeric G protein, Gαq/11, resulting in the activation of phospholipase C, the release of Ca(2+) from intracellular stores and the subsequent activation of protein kinase C. However, it is now recognized that mGluR5a also functions as a receptor for cellular prion protein (PrP(C)) and β-amyloid peptide (Aβ42) oligomers to facilitate intracellular signaling via the resulting protein complex. Intracellular mGluR5a signaling is also regulated by its association with a wide variety of intracellular regulation proteins.

Role of SAP97 in the regulation of 5-HT2AR endocytosis and signaling.

Serotonin (5-HT) interacts with a wide variety of 5-HT receptors (5-HTR) of which 5-HT2AR plays an important target for antidepressant and atypical antipsychotic drugs. The carboxyl-terminal tail of 5-HT2AR encodes a motif that mediates interactions with PSD-95/disc large/zona occludens (PDZ) domain-containing proteins. In the present study, we found that 5-HT2AR interacts with synapse-associated protein 97 (SAP97; also known as DLG1) by coimmunoprecipitation in human embryonic 293 (HEK 293) cells and cortical brain lysates.

Three-dimensional peak and cumulative shoulder loads and postures during non-occupational tasks: a preliminary investigation.

Background: In order to obtain a complete understanding of the etiology of upper extremity musculoskeletal disorders, a spectrum of risk factors needs to be evaluated, within and external to the workplace. To date, cumulative shoulder loads (forces and moments) have only been documented during automotive assembly tasks. No information on shoulder loads during non-occupational tasks has been reported.

Role of SAP97 protein in the regulation of corticotropin-releasing factor receptor 1 endocytosis and extracellular signal-regulated kinase 1/2 signaling.

The corticotropin-releasing factor (CRF) receptor 1 (CRFR1) is a target for the treatment of psychiatric diseases such as depression, schizophrenia, anxiety disorder, and bipolar disorder. The carboxyl-terminal tail of the CRFR1 terminates in a PDZ-binding motif that provides a potential site for the interaction of PSD-95/Discs Large/Zona Occludens 1 (PDZ) domain-containing proteins. In this study, we found that CRFR1 interacts with synapse-associated protein 97 (SAP97; also known as DLG1) by co-immunoprecipitation in human embryonic 293 (HEK 293) cells and cortical brain lysates and that this interaction is dependent upon an intact PDZ-binding motif at the end of the CRFR1 carboxyl-terminal tail.

The angiotensin II type 1 receptor induces membrane blebbing by coupling to Rho A, Rho kinase, and myosin light chain kinase.

The angiotensin II type 1 receptor (AT(1)R) is a G alpha(q/11)-coupled G protein-coupled receptor that is widely expressed in multiple tissues, including vascular smooth muscle cells, brain, and kidney. Activation of the AT(1)R in vascular smooth muscle cells leads to alterations in actin-based membrane protrusions such as lamellipodia, filopodia, and membrane blebs that ultimately lead to cell migration, which is important for the regulation of vascular tone. In the present study, we examine the role of small G proteins in mediating AT(1)R-induced alterations in membrane dynamics in human embryonic kidney 293 cells.

The small GTPase Ral couples the angiotensin II type 1 receptor to the activation of phospholipase C-delta 1.

The angiotensin II type 1 receptor (AT(1)R) plays an important role in cardiovascular function and as such represents a primary target for therapeutic intervention. The AT(1)R has traditionally been considered to be coupled to the activation of phospholipase C (PLC) beta via its association with G alpha(q/11), leading to increases in intracellular inositol phosphate (IP) and release of calcium from intracellular stores. In the present study, we investigated whether the small GTPase RalA contributed to the regulation of AT(1)R endocytosis and signaling.

Inhibition of metabotropic glutamate receptor signaling by the huntingtin-binding protein optineurin.

Huntington disease is caused by a polyglutamine expansion in the huntingtin protein (Htt) and is associated with excitotoxic death of striatal neurons. Group I metabotropic glutamate receptors (mGluRs) that are coupled to inositol 1,4,5-triphosphate formation and the release of intracellular Ca(2+) stores play an important role in regulating neuronal function. We show here that mGluRs interact with the Htt-binding protein optineurin that is also linked to normal pressure open angled glaucoma and, when expressed in HEK 293 cells, optineurin functions to antagonize agonist-stimulated mGluR1a signaling.

Ral and phospholipase D2-dependent pathway for constitutive metabotropic glutamate receptor endocytosis.

G-protein-coupled receptors play a central role in the regulation of neuronal cell communication. Class 1 metabotropic glutamate receptors (mGluRs) mGluR1a and mGluR5a, which are coupled with the hydrolysis of phosphoinositides, are essential for modulating excitatory neurotransmission at glutamatergic synapses. These receptors are constitutively internalized in heterologous cell cultures, neuronal cultures, and intact neuronal tissues.