Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.1.4.3 (phospholipase C)
18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Monoclonal antibodies to opioid-binding cell adhesion molecule (OBCAM) were produced against a synthetic OBCAM peptide. Immunoblotting analysis revealed that the antibodies reacted with 58 and/or 51 kDa proteins in P2 membranes from bovine, rat, mouse, guinea pig and rabbit brains. In bovine brain, the 58 and 51 kDa proteins were present in the striatum and cerebral cortex at high levels, but not in the pituitary. OBCAM was also detected in the cerebellum mainly in the 51 kDa form. In other tissues, the proteins were found in the spleen at very low levels, but not at all in the liver or kidney of the rat. OBCAM was effectively solubilized from bovine P2 membranes by bacterial phosphatidylinositol specific-phospholipase C (PI-PLC), indicating that OBCAM is a glycosylphosphatidylinositol (GPI)-anchored protein. PI-PLC treatment, however, had little effect on the opioid binding activity of the residual P2 membranes. The molecular weight of the proteins (58 and 51 kDa) was reduced to 36 kDa following treatment with N-glycanase but not further reduced after subsequent treatment with neuraminidase and O-glycanase, suggesting that OBCAM has N-glycosylated carbohydrate chains and that its two isoforms are different, at least, in the degree of N-glycosylation. Taken together, these results suggest that OBCAM consists of 58/51 kDa GPI-anchored glycoproteins which are highly N-glycosylated and are expressed mainly in the nervous system.
...
PMID:Characterization and tissue distribution of opioid-binding cell adhesion molecule (OBCAM) using monoclonal antibodies. 874 Apr 43

Previously, our laboratory purified and isolated the cDNA for OBCAM (opioid binding cell adhesion molecule) from bovine brain, as well as highly homologous rat brain cDNA clones, SG13 and DUZ-1. Structural similarities with members of the immunoglobulin superfamily suggest a possible role for OBCAM in cell adhesion and recognition, while studies in our own laboratory suggest that OBCAM is important in the regulation of opioid binding and signal transduction. However, OBCAM lacks a putative transmembrane domain, and its possible mode of linkage to the cellular membrane has not been studied. Upon transfection of Cos 1 cells with SG13 and DUZ-1 cDNAs, the OBCAM-homologous proteins were expressed on the surface of the Cos 1 cells. These proteins were released from the membrane of the Cos 1 cells upon digestion with phosphatidylinositol-specific phospholipase C (PI-PLC), demonstrating that they are linked to the membrane via a phosphatidylinositol (PI) linkage. These results are consistent with a role for OBCAM in cell recognition and adhesion, as well as in cellular signaling.
...
PMID:Expression of OBCAM-related cDNA clones in Cos 1 cells: evidence for a phosphatidylinositol linkage to the cell membrane. 896 53

Neurotrimin (Ntm) together with the limbic system-associated membrane protein (LAMP) and the opioid-binding cell adhesion molecule (OBCAM) comprise the IgLON family of neural cell adhesion molecules. These glycosylphosphatidylinositol (GPI)-anchored proteins are expressed in distinct neuronal systems. In the case of Ntm, its expression pattern suggests a role in the development of thalamocortical and pontocerebellar projections (Struyket al., 1995). We have now characterized Ntm's function in cell adhesion and in neurite outgrowth. Cross-linking studies of transfected cells show that Ntm forms noncovalent homodimers and multimers at the cell surface. Ntm mediates homophilic adhesion, as evidenced by the reaggregation of the transfected cells and the specific binding of an Ntm-Fc chimera to these cells. Consistent with these results, Ntm-Fc binds to neurons that express Ntm at high levels, e.g., dorsal root ganglion (DRG) and hippocampal neurons. It does not bind to DRG neurons treated with phosphatidylinositol-specific phospholipase C (PI-PLC) or to sympathetic neurons that do not express Ntm or other members of the IgLON family at significant levels. Ntm promotes the outgrowth of DRG neurons, even after PI-PLC treatment, suggesting that its effects on outgrowth are mediated by heterophilic interactions. Of particular note, both membrane-bound and soluble Ntm inhibit the outgrowth of sympathetic neurons. These results strongly suggest that Ntm, and other members of the IgLON family, regulate the development of neuronal projections via attractive and repulsive mechanisms that are cell type specific and are mediated by homophilic and heterophilic interactions.
...
PMID:Neurotrimin mediates bifunctional effects on neurite outgrowth via homophilic and heterophilic interactions. 980 70

In the central nervous system, many cell adhesion molecules are known to participate in the establishment and remodeling of the neural circuit. Some of the cell adhesion molecules are known to be anchored to the membrane by the glycosylphosphatidylinositol (GPI) inserted to their C termini, and many GPI-anchored proteins are known to be localized in a Triton-insoluble membrane fraction of low density or so-called "raft." In this study, we surveyed the GPI-anchored proteins in the Triton-insoluble low density fraction from 2-week-old rat brain by solubilization with phosphatidylinositol-specific phospholipase C. By Western blotting and partial peptide sequencing after the deglycosylation with peptide N-glycosidase F, the presence of Thy-1, F3/contactin, and T-cadherin was shown. In addition, one of the major proteins, having an apparent molecular mass of 36 kDa after the peptide N-glycosidase F digestion, was found to be a novel protein. The result of cDNA cloning showed that the protein is an immunoglobulin superfamily member with three C2 domains and has six putative glycosylation sites. Since this protein shows high sequence similarity to IgLON family members including LAMP, OBCAM, neurotrimin, CEPU-1, AvGP50, and GP55, we termed this protein Kilon (a kindred of IgLON). Kilon-specific monoclonal antibodies were produced, and Western blotting analysis showed that expression of Kilon is restricted to brain, and Kilon has an apparent molecular mass of 46 kDa in SDS-polyacrylamide gel electrophoresis in its expressed form. In brain, the expression of Kilon is already detected in E16 stage, and its level gradually increases during development. Kilon immunostaining was observed in the cerebral cortex and hippocampus, in which the strongly stained puncta were observed on dendrites and soma of pyramidal neurons.
...
PMID:Characterization of a novel rat brain glycosylphosphatidylinositol-anchored protein (Kilon), a member of the IgLON cell adhesion molecule family. 1007 27

Opioid-binding cell adhesion molecule (OBCAM) belongs to the immunoglobulin superfamily CAMs and shows a dendritically polarized distribution in hypothalamic magnocellular neurons. In the present study, the cellular localization of OBCAM was monitored in cultured cortical and hippocampal neurons to examine its polarized distribution. Double labeling immunofluorescence microscopy after fixation showed only faint OBCAM immunoreactivity in the neuronal somata during the early stages of culture, whereas the immunoreactivity was strong in MAP2-positive somata and dendrites of fully polarized neurons after longer culture. Moreover, the immunoreactivity for OBCAM showed a punctate pattern in the dendrites similar to the immunostaining pattern of synapsin I. High resolution revealed close apposition with only a partial overlap of synapsin I and OBCAM immunoreactivities, suggesting the synaptic localization of OBCAM to the dendrites. When the fully polarized neurons were reacted with anti-OBCAM antibody before fixation, OBCAM immunoreactivity became stronger on the dendritic surface than the somatic surface. Extracellular immunoreactivity was eliminated with phosphatidylinositol-specific phospholipase C and this immunoreactivity resisted extraction with the nonionic detergent Triton X-100 at 4 degrees C, indicating that OBCAM is attached to the rafts via a glycosylphosphatidyl inositol anchor. These results indicate that OBCAM is efficiently targeted to the dendritic surface of fully polarized cortical and hippocampal neurons. OBCAM is, hence, concluded to be a dendrite-associated CAM in cortical and hippocampal neurons as in hypothalamic magnocellular neurons.
...
PMID:Polarized targeting of IgLON cell adhesion molecule OBCAM to dendrites in cultured neurons. 1285 May 79

Opioid-binding cell adhesion molecule (OBCAM) is a member of the immunoglobulin superfamily containing limbic system-associated membrane protein (IgLON) subgroup of glycosylphosphatidylinositol-anchored immunoglobulin cell adhesion molecules. We have previously found that OBCAM is localized preferentially to dendrites compared with somata and terminals of hypothalamic vasopressin-secreting magnocellular neurons. This localization indicates that OBCAM is one of the dendrite-associated cell adhesion molecules. In the present study, we further characterized the localization and the sorting mechanism, and activity-dependent changes of this molecule in vasopressin-secreting magnocellular dendrites. Confocal microscopic observation revealed the preferential localization of OBCAM at the neurosecretory granules in the vasopressin-positive dendrites. Electron microscopic observation using chromogen-intensified and gold-conjugated methods also demonstrated the OBCAM labeling at most of the neurosecretory granules within the dendrites, while the labeling within the somata was observed at only a few neurosecretory granules. I.c.v. colchicine administration resulted in the disappearance of OBCAM immunoreactivity from the dendrites and in its concomitant accumulation at the somata, suggesting that OBCAM is synthesized at the somata and transported to the dendrites by dendrite-associated neurosecretory granules. During the postnatal development, OBCAM immunoreactivity targeted to vasopressin-positive dendrites became clear from at least 3 weeks after birth, although it appeared at only a few somata 2 weeks after birth. Phosphatidylinositol specific phospholipase C treatment of the membrane fraction of the supraoptic homogenate solubilized OBCAM. Kilon, another IgLON member, was also shown to localize at the neurosecretory granules of vasopressin-positive dendrites via the glycosylphosphatidylinositol anchor. High K(+)-stimulation appeared to cause the diffusion of OBCAM-labeled gold particles from neurosecretory granules together with the exocytosis. These findings indicate that OBCAM is synthesized within the somata, attached to vasopressin neurosecretory granules via the glycosylphosphatidylinositol anchor, and transported to the dendrites. Moreover, the subcellular localization of OBCAM is changed in an activity-dependent manner.
...
PMID:Dendrite-associated opioid-binding cell adhesion molecule localizes at neurosecretory granules in the hypothalamic magnocellular neurons. 1459 58

---