Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.52 (PNGase F)
 1,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have isolated four insulin-like growth factor binding proteins (IGFBPs) from adult human serum by insulin-like growth factor (IGF) I affinity chromatography and high performance liquid chromatography. A 36-kDa binding protein (BP), not digestible with N-glycanase, is increased in patients with extrapancreatic tumor hypoglycemia and during IGF I administration in healthy adults. Its 38 NH2-terminal amino acids are identical to those of an IGFBP sequence derived from a human cDNA that cross-hybridizes with the rat IGFBP-2 cDNA. With probes encoding a NH2-terminal, COOH-terminal, and a middle region of this protein we have obtained three cDNA clones from a Hep G2 cDNA library; one encodes human IGFBP-2, and the other two presumably represent unspliced heteronuclear and alternatively spliced mRNA, respectively. A 28-30-kDa IGFBP represents a novel BP species in human serum. Its 30 NH2-terminal amino acids are not homologous to IGFBP-1, -2, or -3. It is not digestible with N-glycanase and does not bind 125I-IGF I. The NH2-terminal sequences of a 42/45- and a 31-kDa IGFBP are identical to that of human IGFBP-3. The 42/45-kDa proteins are two glycosylation variants of BP-3. The 31-kDa protein presumably is a degradation product of BP-3 that lacks the COOH terminus. It is likely that the different IGFBPs modulate auto-/paracrine and endocrine effects of IGFs on growth and metabolism in a different and specific manner.
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PMID:Isolation from adult human serum of four insulin-like growth factor (IGF) binding proteins and molecular cloning of one of them that is increased by IGF I administration and in extrapancreatic tumor hypoglycemia. 169 83

Mutation of the 3' splice sites bordering exon 2 of the H-2Dd and H-2Kd genes generated alternatively spliced transcripts when the constructs were transfected into L cells (J. Immunol. 143:1018). The H-2Dd transcripts contained an additional 84 nucleotides derived from the first intervening sequence, whereas 60 extra bases were included in the H-2Kd mRNA. Proteins derived from these transcripts were recognized by mAb. Moreover, both Ag served as recognition elements for CTL, and the mutant H-2Kd molecule functioned as a restricting element for an Ag peptide. As a result of alternative splicing, the mutant proteins should have additional residues at their NH2 termini to increase their lengths by 28 (Dd) or 20 (Kd) amino acids. Immunoprecipitation and analysis on SDS-PAGE demonstrated that the mutant H-2Kd molecule was indeed larger than the normal H-2Kd protein, but the mutant and wild-type H-2Dd Ag were the same size. In addition, treatment of H-2Dd mutant and normal Ag with N-glycanase produced molecules of equal size, demonstrating that the mutant protein was completely glycosylated. Limited amino acid sequencing of this Ag indicated that it was normal H-2Dd. Therefore, before its transfer to the cell surface, post-translational modifications remove the additional NH2-terminal residues of the mutant Dd but not Kd protein.
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PMID:Expression of mutant H-2d proteins encoded by class I genes which alternatively process the 5' end of their transcripts. 247 8

One of the hallmarks of mucosal-host defense is the clearance of inhaled Ags by alveolar macrophages (AM) through interactions of IgA Abs and IgA Fc receptors (Fc alpha R). AM constitutively expressed Fc alpha R at lower levels than freshly isolated and in vitro-differentiated monocytes as determined by immunofluorescence using four anti-Fc alpha R mAb. SDS-PAGE analysis of iodinated cell surface proteins revealed that Fc alpha R on AM has an Mr of 50 to 65 kDa, slightly lower than that on monocytes (55-75 kDa). Treatment of AM Fc alpha R by N-glycanase gave rise to a protein core of 28 KDa, smaller than the 32-kDa backbone of blood monocytes. AM Fc alpha R molecules were unaffected by phosphatidylinositol-phospholipase C treatment. Fc alpha R transcripts were analyzed by reverse transcription-PCR using primers in the 5' and 3' regions of a U937 Fc alpha R cDNA. Three transcripts were amplified, cloned, and sequenced from AM and/or monocyte mRNA, the full length Fc alpha R and two alternatively spliced products corresponding to deletions of 66 and 288 nucleotides in the portion coding for the extracellular domain; they were named Fc alpha R a.1, a.2, and a.3, respectively. These PCR products were transcribed and translated in vitro into three proteins (Mr 32, 30, and 22 kDa, respectively), in which the 32- and 30-kDa species were immunoprecipitated by an anti-Fc alpha R mAb. The predicted size of the protein encoded by the Fc alpha R a.2 transcript without the leader peptide is Mr approximately 27,400, a value that is consistent with the Mr of AM Fc alpha R backbone. These results indicate that AM express at their surfaces a protein product of an alternatively spliced Fc alpha R transcript, the Fc alpha R a.2 isoform, that might have physiologic relevance in IgA-mediated host defense at mucosal sites.
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PMID:Identification of Fc alpha receptor (CD89) isoforms generated by alternative splicing that are differentially expressed between blood monocytes and alveolar macrophages. 866 19

The interaction between the colon tumor cell surface and the endothelial cell layer is an important component of tumor intravasation, extravasation, and metastasis. Multiple studies suggest that tumor cells may bind to E-selectin expressed on endothelial cells during these processes. To identify possible E-selectin ligands on tumor cells that may participate in this mechanism, we used E-selectin-Ig chimera affinity chromatography to isolate glycoproteins from the human colon cancer cell line Colo-205. Binding of these cells to E-selectin was specific, required the presence of calcium, and could be blocked by antibodies against E-selectin. We identified LAMP-1 (lysosomal membrane glycoprotein-1), LAMP-2, and two high molecular weight glycoproteins (>400 kDa and 300 kDa) as the main E-selectin ligands on Colo-205 cells. Treatment of the cells with N-glycanase and O-sialoglycoprotease abolished their binding to E-selectin. The high MW glycoproteins contained sialyl Lewis X and/or sialyl Lewis A glycoconjugates, and appeared to be either alternatively spliced or alternatively glycosylated forms of MUC-1 (mucin-1).
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PMID:Human colon cancer cells express multiple glycoprotein ligands for E-selectin. 1063 80

One form of inherited long QT syndrome, LQT2, results from mutations in HERG1, the human ether-a-go-go-related gene, which encodes a voltage-gated K(+) channel alpha subunit. Heterologous expression of HERG1 gives rise to K(+) currents that are similar (but not identical) to the rapid component of delayed rectification, I(Kr), in cardiac myocytes. In addition, N-terminal splice variants of HERG1 and MERG1 (mouse ERG1) referred to as HERG1b and MERG1b have been cloned and suggested to play roles in the generation of functional I(Kr) channels. In the experiments here, antibodies generated against HERG1 were used to examine ERG1 protein expression in heart and in brain. In Western blots of extracts of QT-6 cells expressing HERG1, MERG1, or RERG1 (rat ERG1) probed with antibodies targeted against the C terminus of HERG1, a single 155-kDa protein is identified, whereas a 95-kDa band is evident in blots of extracts from cells expressing MERG1b or HERG1b. In immunoblots of fractionated rat (and mouse) brain and heart membrane proteins, however, two prominent high molecular mass proteins of 165 and 205 kDa were detected. Following treatment with glycopeptidase F, the 165- and 205-kDa proteins were replaced by two new bands at 175 and 130 kDa, suggesting that ERG1 is differentially glycosylated in rat/mouse brain and heart. In human heart, a single HERG1 protein with an apparent molecular mass of 145 kDa is evident. In rats, ERG1 protein (and I(Kr)) expression is higher in atria than ventricles, whereas in humans, HERG1 expression is higher in ventricular, than atrial, tissue. Taken together, these results suggest that the N-terminal alternatively spliced variants of ERG1 (i.e. ERG1b) are not expressed at the protein level in rat, mouse, or human heart and that these variants do not, therefore, play roles in the generation of functional cardiac I(Kr) channels.
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PMID:Expression of distinct ERG proteins in rat, mouse, and human heart. Relation to functional I(Kr) channels. 1068 94

We have cloned and characterized a novel glucose transporter (GLUT11) that is alternatively spliced. The GLUT11 gene maps to chromosome 22q11.2 and consists of 13 exons. The long form (GLUT11-L) cDNA uses 13 exons to produce a protein containing 503 amino acids. The short form of GLUT11 (GLUT-11) cDNA is missing exon 2 and produces a protein of 496 amino acids with a 14 amino acid N-terminal difference compared to the long form. GLUT11 has significant similarity to known GLUTs and contains 12 putative membrane-spanning helices along with sugar transporter signature motifs that have previously been shown to be essential for transport activity. The putative glycosylation site of GLUT11 is present in loop 1. Northern blot analysis showed that GLUT11 mRNA is expressed in a number of tissues and most abundantly in the skeletal muscle and heart. RT-PCR assay showed that GLUT11 is alternatively spliced and the two isoforms are distributed differently in various tissues. Immunofluorescence microscopy demonstrated that GLUT11-L resides on the plasma membrane when overexpressed in HEK293T cells. Western blot analysis revealed that GLUT11-L runs as a broad band of approximately 42 kDa that was converted to a 38 kDa polypeptide by PNGase F digestion. Furthermore, a liposome reconstitution functional assay showed that GLUT11-L has glucose transport activity.
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PMID:Cloning and characterization of glucose transporter 11, a novel sugar transporter that is alternatively spliced in various tissues. 1217 79