Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:O76050 (neu)
 3,969 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Microfilaments are associated with the microvillar membrane in the 13762 ascites rat mammary carcinoma cells by stable interaction with a large, multimeric signal transduction particle (STP) containing the (proto)oncogene receptor p185(neu). In vitro kinase assays on isolated microvilli and microvillar fractions enriched in the putative signal transduction particle showed a high specific activity of tyrosine kinase activity compared to that of membranes from EGF receptor-overexpressing A431 cells maximally activated by EGF. Assays of velocity sedimentation fractions from microvillar lysates in the presence and absence of the exogenous tyrosine kinase substrate poly-glu-tyr polypeptide (poly-E(4)Y) suggested association of the tyrosine kinase activity with STP-enriched microvillar fractions. The particulate fractions also contained discrete endogenous tyrosine-phosphorylated proteins, including prominent bands of approximately 42 and 58 kDa. Addition of ATP to these fractions resulted in a rapid increase in tyrosine phosphorylation of these and several other proteins, as detected by anti-phosphotyrosine blots. Immunoprecipitation and immunoblotting with anti-phosphotyrosine antibody of SDS-solubilized ascites cells and microfilament core fractions showed nine major bands; the electrophoretic mobilities of most of these in the cell immunoprecipitate and microfilament core were the same. In vivo and in situ phosphorylation, phosphoamino acid analysis, immunoprecipitation, 2-dimensional isoelectric focusing/SDS PAGE and immunoblot analysis showed that one of the prominent substrates is p58(gag), a retroviral Gag-like cytoplasmic STP component implicated in stabilizing microfilament-membrane interactions. Immunoblotting identified two peripheral membrane tyrosine kinases, p6O(src) and p120(abl), stably associated with the p185(neu)-containing signal transduction particle. These results provide further evidence for the constitutive activation of this aggressive mammary tumor and suggest a rote for phosphorylation of p58(gag) in organization of the STP at the membrane-microfilament interface in these cells.
 ...
PMID:Tyrosine phosphorylation at the membrane-microfilament interface: a p185neu-associated signal transduction particle containing Src, Abl and phosphorylated p58, a membrane- and microfilament-associated retroviral gag-like protein. 864 94

Microfilaments associate with the microvillar membrane of 13762 ascites mammary adenocarcinoma cells via a large transmembrane complex (TMC) comprising the major glycoproteins TMC-gp120, -110, -80, -65, and -55, the receptor kinase p185(neu), and the cytoplasmic proteins actin and p58(gag), linking the receptor with microfilaments in a signal transduction particle. Immunoblot screening with polyclonal antisera to TMC glycoproteins showed selective epithelial expression in normal rat tissues and epithelially derived tumor cells. The TMC glycoproteins were isolated by solubilization of microfilament core preparations in SDS, dilution, and separation on a concanavalin A-agarose affinity column. The large p185(neu)-containing complex was reconstituted from the column eluate after displacement of SDS with nonionic detergent, demonstrated by gel filtration and co-immunoprecipitation of the glycoproteins with anti-gp55 or anti-p185(neu). Exhaustive biotinylation of the glycoproteins gave a stoichiometry of gp120:gp110:gp80:gp65:gp55 of approximately 1:1:1:0.5:1. Overlay blots with biotinylated actin and in vitro translated, [(35)S]methionine-labeled p58(gag), respectively, showed specific interactions of actin with gp55 and gp120 and of p58(gag) with gp65 and gp55. These results provide evidence for a specific complex of microfilament-associated glycoproteins containing p185(neu) and p58(gag) and suggest a role for the complex in signal transduction scaffolding.
 ...
PMID:The p185(neu)-containing glycoprotein complex of a microfilament-associated signal transduction particle. Purification, reconstitution, and molecular associations with p58(gag) and actin. 1046 1