Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The proteins of microvilli prepared from pig kidney were analysed by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. The typical pattern stained for protein revealed five major bands, four of which also stained for carbohydrate, and about 15 minor bands. For descriptive purposes the bands were designated numerically by their apparent molecular weights (X10(-3). Well-characterized proteins were identified with four of the five major bands. Dipeptidyl peptidase IV, a serine proteinase that may be specifically labelled with di-isopropyl [32P]phosphorofluoridate, was assigned to band 130. Aminopeptidase M was assigned to band 160, though when released from the membrane by a proteinase, this protein comprises three polypeptides each of lower apparent molecular weight than the native enzyme. Neutral endopeptidase can be assigned to band 95 and actin to band 42. The fifth major band (180) is an extrinsic glycoprotein that has not been identified with any microvillus enzyme activity. These four proteins contribute 21% of the microvillus-membrane protein. Kidney microvillus actin was characterized by a variety of properties and was similar to muscle actin. A computer analysis of the gel pattern indicates that it comprises 9.0% of the microvillus protein. Myosin is not present in the microvillus, but another protein associated with band 95, with properties that distinguish it from neutral endopeptidase, was tentatively identified as alpha-actinin. Alkaline phosphatase was identified as a monomeric polypeptide with an apparent molecular weight of 80000; it is a minor protein of the microvillus and is not discernible as a discrete band in the gel pattern. These and other results permit a model of the organization of the microvillus protein to be suggested. The computer program used has been deposited as Supplementary Publication SUP 50070 (12 pages) at the British Library Lending Division, Boston Spa. Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms given in Biochem. J. (1976) 153,5.
 ...
PMID:Proteins of the kidney microvillus membrane. Identification of subunits after sodium dodecylsullphate/polyacrylamide-gel electrophoresis. 13 63

Endopeptidase-24.18 (endopeptidase-2, EC 3.4.24.18, E-24.18) is a Zn-ectoenzyme of rat renal and intestinal microvillar membranes exhibiting an oligomeric structure, alpha 2-beta 2. The primary structure of the alpha-subunit of E-24.18 has been defined by molecular cloning and its expression mapped in rat kidney by in situ hybridization. A 2.9-kb cDNA coding for the alpha-subunit was isolated and sequenced. It had an open reading frame of 2,244 base pairs coding for a type I membrane protein of 748 amino acids. The deduced amino acid sequence showed 87% identity with that of meprin A, a mouse metallo-endopeptidase, sharing common properties with the rat enzyme, and 85% identity with the human intestinal enzyme, 'PABA-peptide hydrolase'. Northern blot analysis revealed the alpha-subunit to be encoded by a single mRNA species of 3.2-kb. In situ hybridization performed on rat kidney showed a co-localization of E-24.18 with endopeptidase-24.11 in proximal tubules of juxtamedullary nephrons, suggesting that the two enzymes have similar or complementary physiological functions in kidney.
 ...
PMID:Molecular cloning of the alpha-subunit of rat endopeptidase-24.18 (endopeptidase-2) and co-localization with endopeptidase-24.11 in rat kidney by in situ hybridization. 150 84

A prominent membrane protein of rat type II alveolar cells, p146, was originally identified by one of many mouse monoclonal antibodies that were produced to rat lung cells in the course of a search for differentiation antigens that might prove useful in studying lung differentiation. We report here results from analysis of the primary structure of this molecule and, based on this knowledge, the elucidation of the function of the protein. Amino acid sequencing of the NH2-terminal portion of the p146 protein, plus partial sequencing of several peptides obtained by limited proteolysis, indicates it is identical to aminopeptidase N. Further, the immunoaffinity purified p146 protein has aminopeptidase N activity. The discussion includes references to other molecules such as CD 13 and CD 10 (CALLA) that were recognized as differentiation antigens and subsequently found to be peptidases. The possible biological implications of such a peptidase on the luminal surface of type II alveolar cells are also considered.
 ...
PMID:p146 type II alveolar epithelial cell antigen is identical to aminopeptidase N. 167 22

Latent Epstein-Barr virus (EBV) infection and growth transformation of B lymphocytes is characterized by EBV nuclear and membrane protein expression (EBV nuclear antigen [EBNA] and latent membrane protein [LMP], respectively). LMP1 is known to be an oncogene in rodent fibroblasts and to induce B-lymphocyte activation and cellular adhesion molecules in the EBV-negative Burkitt's lymphoma cell line Louckes. EBNA-2 is required for EBV-induced growth transformation; it lowers rodent fibroblast serum dependence and specifically induces the B-lymphocyte activation antigen CD23 in Louckes cells. These initial observations are now extended through an expanded study of EBNA- and LMP1-induced phenotypic effects in a different EBV-negative B-lymphoma cell line, BJAB. LMP1 effects were also evaluated in the EBV-negative B-lymphoma cell line BL41 and the EBV-positive Burkitt's lymphoma cell line, Daudi (Daudi is deleted for EBNA-2 and does not express LMP). Previously described EBNA-2- and LMP1-transfected Louckes cells were studied in parallel. EBNA-2, from EBV-1 strains but not EBV-2, induced CD23 and CD21 expression in transfected BJAB cells. In contrast, EBNA-3C induced CD21 but not CD23, while no changes were evident in vector control-, EBNA-1-, or EBNA-LP-transfected clones. EBNAs did not affect CD10, CD30, CD39, CD40, CD44, or cellular adhesion molecules. LMP1 expression in all cell lines induced growth in large clumps and expression of the cellular adhesion molecules ICAM-1, LFA-1, and LFA-3 in those cell lines which constitutively express low levels. LMP1 expression induced marked homotypic adhesion in the BJAB cell line, despite the fact that there was no significant increase in the high constitutive BJAB LFA-1 and ICAM-1 levels, suggesting that LMP1 also induces an associated functional change in these molecules. LMP1 induction of these cellular adhesion molecules was also associated with increased heterotypic adhesion to T lymphocytes. The Burkitt's lymphoma marker, CALLA (CD10), was uniformly down regulated by LMP1 in all cell lines. In contrast, LMP1 induced unique profiles of B-lymphocyte activation antigens in the various cell lines. LMP1 induced CD23 and CD39 in BJAB; CD23 in Louckes; CD39 and CD40 in BL41; and CD21, CD40, and CD44 in Daudi. In BJAB, CD23 surface and mRNA expression were markedly increased by EBNA-2 and LMP1 coexpression, compared with EBNA-2 or LMP1 alone. This cooperative effect was CD23 specific, since no such effect was observed on another marker, CD21.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Epstein-Barr virus latent membrane protein (LMP1) and nuclear proteins 2 and 3C are effectors of phenotypic changes in B lymphocytes: EBNA-2 and LMP1 cooperatively induce CD23. 215 87

Epstein-Barr virus (EBV)-positive Burkitt's lymphoma (BL) biopsy cells and early passage BL cell lines have been reported as showing an unusual type of virus-cell interaction; at least two EBV latent proteins appear not to be expressed. Serial passage of such lines is often accompanied by a broadening of virus latent gene expression and a corresponding change in the cell surface/growth phenotype towards that shown by in vitro transformed lymphoblastoid cell lines (LCLs). The sequence of events, both viral and cellular, involved in this transition needs to be defined properly. In the present work, phenotypically distinct cell clones have been derived from early passage cultures of a BL cell line in phenotypic transition, thereby giving access to relatively stable cell populations through which the different EBV-B cell interactions within the parental line can be studied. Clones retaining the original BL biopsy cell phenotype (CD10/CD77-positive, activation antigen/adhesion molecule-negative) expressed the virus-encoded nuclear antigen EBNA 1 but not any of the other known latent proteins, EBNAs 2, 3a, 3b, 3c, -LP and latent membrane protein (LMP). Other clones which had developed an LCL-like phenotype (CD10/CD77-negative, activation antigen/adhesion molecule-positive) now expressed all the above latent proteins and also contained significant numbers of cells in lytic cycle. Phenotypic change occurring within the parental BL cell line itself was initiated in a small subpopulation of cells in which the virus-encoded proteins EBNA 2 and LMP were transiently induced to an unusually high level of expression; this was accompanied by the first detectable changes in cell surface phenotype, namely the increase of cellular adhesion molecules. Some control over EBNA 2/LMP expression then appeared to be re-imposed since the presumed clonal descendents of these cells stably expressed EBNA 2 and LMP at much reduced levels typical of those seen in conventional LCLs.
 ...
PMID:Different Epstein-Barr virus-B cell interactions in phenotypically distinct clones of a Burkitt's lymphoma cell line. 216 33

1. The L-type Ca2+ current was recorded in guinea-pig ventricular myocytes by the patch clamp technique in the whole-cell configuration. The modification of the current by intracellular application of proteases was studied. 2. During the first phase of action, trypsin, an endopeptidase, increased the amplitude of Ca2+ current about 3-fold. 3. Thereafter, there was a drastic slowing of the inactivation time course of the enhanced Ca2+ current. The half-time of inactivation increased from a control value of about 25 ms to values larger than 200 ms. 4. Cell dialysis with carboxypeptidase A, an exopeptidase, also enlarged the amplitude of Ca2+ current, but did not affect the kinetics of Ca2+ current. Leuaminopeptidase did not modify the Ca2+ current. 5. The hypothesis that Ca2+ channels are affected by the protease is supported by the fact that alterations of the extracellular Na+ or K+ concentration did not influence the modification of the membrane current. Another argument for the involvement of Ca2+ channels is that the modified membrane current could be blocked by inorganic and organic Ca2+ channel blockers (e.g. 10 microM-Cd2+, 100 microM-La3+ or 1 microM-D600). 6. Although the actions of trypsin and maximal concentrations of isoprenaline on the amplitude of the Ca2+ current were not additive, the slowing of inactivation by trypsin occurred independently from beta-adrenergic stimulation. 7. The effect of trypsin on the Ca2+ current could not be blocked by intracellular 5'-adenylyl-imidodiphosphate (AMP-PNP) or Rp-adenosine 3'5'-monothionophosphate (Rp-cAMPS), both of which are known to suppress the cyclic AMP-dependent phosphorylation of the Ca2+ channel. 8. It was concluded that trypsin may directly modify the membrane protein which forms the Ca2+ channel. Since the increment in peak Ca2+ current resembled the action of cyclic AMP-dependent phosphorylation, it may be related to the removal of a 'chemical' inactivation gate which is normally controlled by phosphorylation. The slowing of the time course of Ca2+ current inactivation by trypsin could be due to a modification of the voltage-dependent inactivation gate. Alternatively, the endopeptidase might remove an internal Ca2+ binding site normally responsible for Ca2+-dependent inactivation.
 ...
PMID:Modification of L-type calcium current by intracellularly applied trypsin in guinea-pig ventricular myocytes. 285 49

The property of solutions of Triton X-114 to separate into detergent-rich and detergent-poor phases at 30 degrees C has been exploited to investigate the identities of the aminopeptidases in synaptic membrane preparations from pig striatum. When titrated with an antiserum to aminopeptidase N (EC 3.4.11.2), synaptic membranes solubilized with Triton X-100 revealed that this enzyme apparently comprises no more than 5% of the activity releasing tyrosine from [Leu]enkephalin. When assayed in the presence of puromycin, this proportion increased to 20%. Three integral membrane proteins were fractionated by phase separation in Triton X-114. Aminopeptidase activity, endopeptidase-24.11 and peptidyl dipeptidase A partitioned predominantly into the detergent-rich phase when kidney microvillar membranes were so treated. However, only 5.5% of synaptic membrane aminopeptidase activity partitioned into this phase, although the other peptidases behaved predictably. About half of the aminopeptidase activity in the detergent-rich phase could now be titrated with the antiserum, showing that aminopeptidase N is an integral membrane protein of this preparation. Three aminopeptidase inhibitors were investigated for their ability to discriminate between the different activities revealed by these experiments. Although amastatin was the most potent (IC50 = 5 X 10(-7) M) it failed to discriminate between pure kidney aminopeptidase N, the total activity of solubilized synaptic membranes and that in the Triton X-114-rich phase. Bestatin was slightly more potent for total activity (IC50 = 6.3 X 10(-6) M) than for the other two forms (IC50 = 1.6 X 10(-5) M). Puromycin was a weak inhibitor, but was more selective. The activity of solubilized membranes was more sensitive (IC50 = 1.6 X 10(-5) M) than that of the pure enzyme or the Triton X-114-rich phase (IC50 = 4 X 10(-4) M). We suggest that the puromycin-sensitive aminopeptidase activity that predominates in crude synaptic membrane preparations may be a cytosolic contaminant or peripheral membrane protein rather than an integral membrane component. Aminopeptidase N may contribute to the extracellular metabolism of enkephalin and other susceptible neuropeptides in the brain.
 ...
PMID:The metabolism of neuropeptides. Phase separation of synaptic membrane preparations with Triton X-114 reveals the presence of aminopeptidase N. 286 52

Pig kidney microvillar proteins were extracted with octyl beta-glucoside and reconstituted in liposomes prepared from microvillar lipids of known composition. Four peptidases, namely endopeptidase (EC 3.4.24.11), aminopeptidases N (EC 3.4.11.2) and A (EC 3.4.11.7) and dipeptidyl peptidase IV (EC 3.4.14.5), were shown to be reconstituted. At lipid/protein ratios greater than 4:1, about half the detergent-solubilized protein and nearly all of the activity of the four peptidases were reconstituted. Dissolution of the liposomes with Triton X-100 did not increase the activity of any of these peptidases, a result consistent with an asymmetric, 'right-side-out', orientation of these enzymes. When purified, endopeptidase was subjected to the same procedure; the two amphipathic forms of the enzyme (the detergent form and the trypsin-treated detergent form) were fully reconstituted. The amphiphilic form, purified after toluene/trypsin treatment, failed to reconstitute. Electron microscopy of microvilli showed that the appearance of the surface particles was profoundly altered by treatment with papain. Before treatment, the microvilli were coated with particles of stalk lengths ranging from 2.5 to 9 nm. After papain treatment nearly all the particles had stalks of 2-3 nm. Reconstituted microvillar proteins in liposomes showed the same heterogeneity of stalk length. In contrast, liposomes containing reconstituted endopeptidase revealed a very homogeneous population of particles of stalk length 2 nm. Since the smallest dimension of a papain molecule is 3.7 nm, the ability of papain, and other proteinases of similar molecular size, to release microvillar enzymes is crucially affected by the length of the junctional peptide that constitutes the stalk of this type of membrane protein.
 ...
PMID:Proteins of the kidney microvillar membrane. Reconstitution of endopeptidase in liposomes shows that it is a short-stalked protein. 634 16

Type II integral membrane proteins are anchored by a signal-peptide/membrane-anchor domain (SA domain) located near their N-terminus, whereas type I membrane proteins are anchored by stop-transfer sequences usually located near the C-terminus. In this study we have attempted to transform neutral endopeptidase-24.11 (EC 3.4.24.11; NEP), a type II membrane protein, into a type I membrane protein. Three type I mutant proteins were constructed by fusion of topogenic sequences to the C-terminus of SecNEP, a soluble form of NEP. The first two type I mutants, SecNEP-TMC and SecNEP-TMIC, were constructed by fusing in frame the cytosolic and SA domains of NEP to the C-terminus of SecNEP. These two fusion proteins differ only in the orientation of the cytosolic tail. The third type I mutant, SecNEP-ACE, was constructed by fusing in frame the stop-transfer and cytosolic domains of angiotensin I-converting enzyme (EC 3.4.15.1; ACE) to the C-terminus of SecNEP. Our results suggest that: (1) the NEP ectodomain can be anchored with a type I topology in the endoplasmic reticulum (ER) membrane by both NEP and ACE topogenic sequences; (2) SecNEP-TMC and SecNEP-TMIC were transport-incompetent and needed proteolytic cleavage in the C-terminal region to leave the ER, whereas SecNEP-ACE was transported out of the ER as a type I membrane protein. Therefore we concluded that the nature of topogenic sequences determines the transport-competence of topological mutants of neutral endopeptidase-24.11.
 ...
PMID:The nature of topogenic sequences determines the transport competence of topological mutants of neutral endopeptidase-24.11. 749 41

Pancreatic acinar cells, a model cell type for the study of exocytosis in non-excitable cells, were used here to test the hypothesis that molecular mechanisms regulating exocytosis from neuronal and neuroendocrine cells may also be utilized in exocrine cells. Using specific antisera raised against vesicle-associated membrane protein (VAMP) isoforms 1 and 2, we have identified VAMP-2, but not VAMP-1, immunoreactive proteins on rat pancreatic acinar cell secretory (zymogen) granules. This 18-kDa protein co-migrated with rat brain synaptic vesicle VAMP-2. Tetanus toxin (TeTx) light chain caused complete cleavage of this protein, which was prevented by the addition of EDTA. This toxin also inhibited in a dose-dependent manner Ca(2+)-stimulated enzyme secretion by up to approximately 30% in streptolysin O-permeabilized acini. This effect of TeTx on secretion was prevented by the zinc endopeptidase inhibitor captopril or by boiling the toxin. Incomplete inhibition of secretion by TeTx may suggest that TeTx-insensitive or VAMP-2-independent mechanisms also regulate exocytosis. In support, TeTx light chain was without effect on Rab3AL (effector domain peptide of Rab3)-mediated potentiation of Ca(2+)-stimulated secretion. These results indicate that a TeTx-sensitive VAMP-2-like protein on zymogen granules participates in Ca(2+)-regulated pancreatic enzyme secretion and that undefined Rab3AL-activated mechanisms may act independently to regulate exocytosis.
 ...
PMID:Tetanus toxin light chain cleaves a vesicle-associated membrane protein (VAMP) isoform 2 in rat pancreatic zymogen granules and inhibits enzyme secretion. 751 31


1 2 3 4 5 6 Next >>