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J Pin

Publications and source records attributed to J Pin.

17 recordsLinked to original sources
PubMed2001

C-terminal interaction is essential for surface trafficking but not for heteromeric assembly of GABA(b) receptors.

Assembly of fully functional GABA(B) receptors requires heteromerization of the GABA(B(1)) and GABA(B(2)) subunits. It is thought that GABA(B(1)) and GABA(B(2)) undergo coiled-coil dimerization in their cytoplasmic C termini and that assembly is necessary to overcome GABA(B(1)) retention in the endoplasmatic reticulum (ER). We investigated the mechanism underlying GABA(B(1)) trafficking to the cell surface. We identified a signal, RSRR, proximal to the coiled-coil domain of GABA(B(1)) that when deleted or mutagenized allows for surface delivery in the absence of GABA(B(2)). A similar motif, RXR, was recently shown to function as an ER retention/retrieval (ERR/R) signal in K(ATP) channels, demonstrating that G-protein-coupled receptors (GPCRs) and ion channels use common mechanisms to control surface trafficking. A C-terminal fragment of GABA(B(2)) is able to mask the RSRR signal and to direct the GABA(B(1)) monomer to the cell surface, where it is functionally inert. This indicates that in the heteromer, GABA(B(2)) participates in coupling to the G-protein. Mutagenesis of the C-terminal coiled-coil domains in GABA(B(1)) and GABA(B(2)) supports the possibility that their interaction is involved in shielding the ERR/R signal. However, assembly of heteromeric GABA(B) receptors is possible in the absence of the C-terminal domains, indicating that coiled-coil interaction is not necessary for function. Rather than guaranteeing heterodimerization, as previously assumed, the coiled-coil structure appears to be important for export of the receptor complex from the secretory apparatus.

Amino Acid Motifs↗
PubMed2001

Molecular determinants of metabotropic glutamate receptor signaling.

Metabotropic glutamate (mglu) receptors are implicated in the regulation of many physiological and pathological processes in the CNS, including synaptic plasticity, learning and memory, motor coordination, pain transmission and neurodegeneration. Several recent studies have elucidated the molecular determinants of mglu receptor signaling and show that several mechanisms acting at different steps in signal propagation are involved. We attempt to offer an integrated view on how homologous and heterologous mechanisms regulate the initial steps of signal propagation, mainly at the level of mglu-receptor-G-protein coupling. Particular emphasis is placed on the role of phosphorylation mechanisms mediated by protein kinase C and G-protein-coupled receptor kinases, and on the emerging importance of some members of the regulators of G-protein signaling family, such as RGS2 and RGS4, which facilitate the GTPase activity that is intrinsic to the alpha-subunits of G(q) and G(i).

GTP-Binding Proteins↗
PubMed1997

A randomized comparison of the clinical and hormonal effects of two GnRH agonists in patients with prostate cancer.

OBJECTIVE: The aims of the study were (i) to compared the efficacy of the two long-acting GnRH agonists (GnRHa) triptorelin (Trp) and leuprolide (Leu) in men with prostate cancer and (ii) to assess the pattern of plasma testosterone levels following each injection of GnRHa. PATIENTS AND METHODS: 67 patients referred for prostate cancer not suitable for surgery were randomly allocated to two treatment regimens: 33 patients received 3.75 mg Trp i.m. at 4-week intervals for 3 months and 34 patients were treated with 3.75 mg Leu s.c. at the same rhythm of administration for 3 months. RESULTS: Clinical data at entry and assessed monthly during follow-up did not differ between the two groups. Plasma prostate-specific antigen (PSA) and testosterone were measured before, 24 and 72 h after each injection of GnRHa. During treatment, PSA dropped similarly in both groups. By month 2, testosterone was < 1.0 nmol/l in 77 and 48% of patients treated with Trp and Leu, respectively (p = 0.02). 24 and 72 h after GnRHa injection, 77 (Trp) and 56% (Leu) of patients had testosterone < 1.0 nmol/l (p < 0.05). CONCLUSIONS: The second and third injections of GnRHa were not followed by a significant increase in testosterone. Trp induced a higher decrease in testosterone than did Leu. The implications in terms of survival should, however, be studied in a larger and longer study.

Antineoplastic Agents, Hormonal↗
PubMed1993

Metabotropic glutamate receptors: an original family of G protein-coupled receptors.

In 1985, we discovered a new glutamate receptor which was coupled to phospholipase C via a G protein and which was later termed metabotropic glutamate receptor (mGluR). In this review, both the diversity of mGluRs and the cellular events they control are discussed, as well as their roles in physiological regulation and brain function.

Animals↗
PubMed1991

[Renin secreting tumor and severe hypertension. Apropos of a new case].

A renin-secreting tumour has been observed in a 32-year-old female with severe hypertension known for 17 years. The excision of the tumour lead to the complete normalisation of the blood pressure. Histological examination showed that the tumour was benign, contained secretion granules at different stages of maturation, and derived from the juxta-glomerular apparatus. After reviewing the 40 cases previously reported in the literature we discuss the clinical presentation of this type of tumour and the approach to their diagnosis.

Adult↗
PubMed1980

[Immuno-allergological study on 30 atopic patients (author's transl)].

An immuno-allergological study was performed on 30 atopic patients and the data were compared to those of 30 healthy controls. The findings were: --increased level of IgE class immunoglobulins in the atopic patients; --increased frequency of the presence of specific reagin to numerous allergens in the sera of atopics (RAST). The total amount of IgE was related to the presence of numerous and/or strongly positive RAST; --immediate hypersensitivity reaction (IHR) to various allergens and specially house-dust. No well-definite correlation was found between IHR and RAST for the same allergens and between the in vitro determination of allergens and a known history of clinical provocation by these allergens. The frequency of positive IHR was related with high level of total IgE; --decreased frequency of delayed cutaneous hypersensitivity tests and specially of those with candidin extracts. Cutaneous hyporeactivity to natural antigens was in relation with high level of total IgE; --no significant statistical difference was found between the amount of T and B lymphocytes; --increased frequency of HLA-A2 group and decreased frequency of HLA-B7 group.

Dermatitis, Atopic↗