Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have characterized a plasma membrane phosphatidylinositol 4,5-bisphosphate (PIP2)-specific phospholipase C (PLC) and a cytosolic phosphatidylinositol (PI)-specific PLC in human liver. Epinephrine, 1 x 10(-5) M, and vasopressin, 1 x 10(-8) M, stimulated PIP2-PLC which was enhanced by guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S). PI-PLC stimulation was not observed by these agents. Insulin and insulin-like growth factors (IGF-I and IGF-II) in the presence and absence of GTP gamma S did not stimulate PIP2-PLC or PI-PLC in plasma membranes and cytosol preparations nor phosphoinositide breakdown in isolated human hepatocytes. Furthermore, serendipitly we found that PIP2-PLC activity was increased in liver membranes from obese patients with type II diabetes when compared to obese and lean controls. We conclude that in human liver, insulin and IGFs are not members of the family of hormones generating inositol trisphosphate (IP3) as a second messenger. Furthermore, the increased PIP2-PLC in diabetic liver may result in: (a) increased intracellular concentrations of IP3 and thus increased Ca2+, which has been postulated to induce insulin resistance; and (b) increased diacylglycerol and thus increased protein kinase C which phosphorylates the insulin receptor at serine residues inactivating the insulin receptor kinase. While the mechanism of increased PIP2-PLC activity in diabetes is unknown, it may initiate a cascade of events that result in insulin resistance.
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PMID:Effect of insulin and insulin-like growth factors I and II on phosphatidylinositol and phosphatidylinositol 4,5-bisphosphate breakdown in liver from humans with and without type II diabetes. 254 Jan 78

Vasopressin V1 receptors were solubilized from rat liver plasma membranes with the detergent lysophosphatidylcholine. [[3H]Arginine]vasopressin (AVP) binding to the solubilized preparations was specific and saturable, with a dissociation constant of 0.6 nM. Cross-linking of [125I]vasopressin to the solubilized fraction, studied by SDS/polyacrylamide-gel-electrophoretic analysis, demonstrated the presence of a 65 kDa band which was specifically labelled with [125I]vasopressin. Specific binding of [3H]AVP to these solubilized receptors was decreased by guanine nucleotides, but not by adenosine 5'-[beta gamma-imido]triphosphate. Addition of vasopressin increased specific binding of 35S-labelled guanosine 5'-[gamma-thio]triphosphate (GTP[35S]) to the solubilized fractions, indicating co-solubilization of GTP-binding protein(s) [G-protein(s)] and vasopressin receptors. The solubilized fraction was insensitive to both cholera- and pertussistoxin treatment. Immunoblotting of the solubilized fraction with antibodies specific for a phosphoinositide-specific phospholipase C (PI-PLC I) demonstrated the presence of a 60 kDa protein. Anti-PI-PLC I antiserum immunoprecipitated solubilized vasopressin-binding sites from rat liver (V1), but not solubilized vasopressin-binding sites from hog kidney (V2). Similar results were obtained with an anti-PI-PLC I IgG affinity column. The solubilized (V1) receptors were enriched by ion-exchange and high-performance gel-filtration liquid chromatography. Vasopressin-binding activity was co-eluted with PI-PLC I and GTP[S]-binding activity on a DEAE-Sepharose column. The major vasopressin- and GTP[35S]-binding activities were co-eluted with PI-PLC I activity at approx. 240 kDa suggesting that vasopressin receptors from rat liver membranes can be solubilized as a complex of receptor-coupler-effector by using the detergent lysophosphatidycholine.
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PMID:Solubilization of rat liver vasopressin receptors as a complex with a guanine-nucleotide-binding protein and phosphoinositide-specific phospholipase C. 254 66

Smooth muscle cells (SMC) express atypical surface low density lipoprotein (LDL) binding proteins of M(r)105 and M(r)130 (p105 and p130) which have been putatively identified as the cell adhesion glycoprotein T-cadherin. Using cultured human and rat aortic SMC and analysis by ligand (LDL)- and immuno-blotting techniques we now confirm identity of p105 and p130 as T-cadherin, as adjudged by sensitivity to PI-PLC cleavage, insensitivity to trypsin degradation in the presence of calcium, and immunoreactivity to anti-T-cadherin peptide antisera. The function of T-cadherin (p105/p130) in the vasculature is unknown. The proteins were downmodulated by the peptide growth factors PDGF-BB, IGF, EGF, and bFGF, but not by vasoactive peptide hormones (angiotensin II, vasopressin, bradykinin, and endothelin). TGF beta, a recognized inhibitor of SMC proliferation, per se had no effect but inhibited growth factor-induced p105/p130 downmodulation. Expression of p105/p130 in quiescent SMC and growth-stimulated SMC (respectively, in serum-free and serum or PDGF-BB containing culture conditions) was increased by forskolin and 8-Br-cyclic GMP, both anti-mitogenic substances, but was unaffected by phorbol ester, calcium ionophores, or calcium antagonists. The findings are compatible with a function for the lipoprotein binding proteins (T-cadherin) in negative regulation of SMC growth.
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PMID:Characteristics of smooth muscle cell lipoprotein binding proteins (p105/p130) as T-cadherin and regulation by positive and negative growth regulators. 961 Mar 89