scholarly journals Molecular cloning of CD68, a human macrophage marker related to lysosomal glycoproteins

Blood ◽  
1993 ◽  
Vol 81 (6) ◽  
pp. 1607-1613 ◽  
Author(s):  
CL Holness ◽  
DL Simmons
Keyword(s):  
Extracellular Domain ◽  
Integral Membrane Protein ◽  
Human Macrophage ◽  
Cdna Clones ◽  
Type I ◽  
Cos Cells ◽  
Transmembrane Glycoprotein ◽  
Macrophage Marker ◽  
Glycosylation Sites ◽  
Low Levels

Abstract CD68 is a 110-Kd transmembrane glycoprotein of unknown function highly expressed by human monocytes and tissue macrophages. We have isolated cDNA clones encoding CD68 from a U937 cDNA library by transient expression in COS cells and panning with the anti-CD68 monoclonal antibodies (MoAbs) Y2/131, Y1/82A, EBM11, and Ki-M6. CD68 transcripts are constitutively present in the promonocyte cell line U937 and are upregulated by phorbol myristic acid (PMA). By contrast, CD68 transcripts are absent or present at very low levels in many hematopoietic lines including KG1, CEM, and K562, but can be induced by exposure to PMA. The cDNA sequence predicts a type I integral membrane protein of 354 residues with a heavily glycosylated extracellular domain of 298 residues containing nine potential N-linked glycosylation sites and numerous potential O-linked glycosylation sites. The extracellular domain consists of two distinct regions separated by an extended proline hinge: a membrane-distal mucin-like domain containing short peptide repeats and consisting of 54% serine and threonine residues; and a membrane proximal domain that has significant sequence homology to a family of lysosomal/plasma membrane shuttling proteins known as the lamp 1 group. CD68 is a member of a growing family of hematopoietic mucin-like molecules, including leukosialin/CD43, the stem cell antigen CD34, and the lymph node high endothelial ligand for L-selectin GlyCAM-1.

scholarly journals Molecular cloning of CD68, a human macrophage marker related to lysosomal glycoproteins

Blood ◽  
1993 ◽  
Vol 81 (6) ◽  
pp. 1607-1613 ◽  
Author(s):  
CL Holness ◽  
DL Simmons
Keyword(s):  
Extracellular Domain ◽  
Integral Membrane Protein ◽  
Human Macrophage ◽  
Cdna Clones ◽  
Type I ◽  
Cos Cells ◽  
Transmembrane Glycoprotein ◽  
Macrophage Marker ◽  
Glycosylation Sites ◽  
Low Levels

CD68 is a 110-Kd transmembrane glycoprotein of unknown function highly expressed by human monocytes and tissue macrophages. We have isolated cDNA clones encoding CD68 from a U937 cDNA library by transient expression in COS cells and panning with the anti-CD68 monoclonal antibodies (MoAbs) Y2/131, Y1/82A, EBM11, and Ki-M6. CD68 transcripts are constitutively present in the promonocyte cell line U937 and are upregulated by phorbol myristic acid (PMA). By contrast, CD68 transcripts are absent or present at very low levels in many hematopoietic lines including KG1, CEM, and K562, but can be induced by exposure to PMA. The cDNA sequence predicts a type I integral membrane protein of 354 residues with a heavily glycosylated extracellular domain of 298 residues containing nine potential N-linked glycosylation sites and numerous potential O-linked glycosylation sites. The extracellular domain consists of two distinct regions separated by an extended proline hinge: a membrane-distal mucin-like domain containing short peptide repeats and consisting of 54% serine and threonine residues; and a membrane proximal domain that has significant sequence homology to a family of lysosomal/plasma membrane shuttling proteins known as the lamp 1 group. CD68 is a member of a growing family of hematopoietic mucin-like molecules, including leukosialin/CD43, the stem cell antigen CD34, and the lymph node high endothelial ligand for L-selectin GlyCAM-1.

scholarly journals Elements of the Endomucin Extracellular Domain Essential for VEGF-Induced VEGFR2 Activity

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1413
Author(s):  
Zhengping Hu ◽  
Issahy Cano ◽  
Kahira L. Saez-Torres ◽  
Michelle E. LeBlanc ◽  
Magali Saint-Geniez ◽  
...  
Keyword(s):  
Extracellular Domain ◽  
Tube Formation ◽  
Vegf Receptor ◽  
Type I ◽  
Downstream Signaling ◽  
Transmembrane Glycoprotein ◽  
Glycosylation Sites ◽  
Domain Truncation ◽  
Endothelial Functions ◽  
Endothelial Growth Factor

Endomucin (EMCN) is the type I transmembrane glycoprotein, mucin-like component of the endothelial cell glycocalyx. We have previously shown that EMCN is necessary for vascular endothelial growth factor (VEGF)-induced VEGF receptor 2 (VEGFR2) internalization and downstream signaling. To explore the structural components of EMCN that are necessary for its function and the molecular mechanism of EMCN in VEGF-induced endothelial functions, we generated a series of mouse EMCN truncation mutants and examined their ability to rescue VEGF-induced endothelial functions in human primary endothelial cells (EC) in which endogenous EMCN had been knocked down using siRNA. Expression of the mouse full-length EMCN (FL EMCN) and the extracellular domain truncation mutants ∆21-81 EMCN and ∆21-121 EMCN, but not the shortest mutant ∆21-161 EMCN, successfully rescued the VEGF-induced EC migration, tube formation, and proliferation. ∆21-161 EMCN failed to interact with VEGFR2 and did not facilitate VEGFR2 internalization. Deletion of COSMC (C1GalT1C1) revealed that the abundant mucin-type O-glycans were not required for its VEGFR2-related functions. Mutation of the two N-glycosylation sites on ∆21-121 EMCN abolished its interaction with VEGFR2 and its function in VEGFR2 internalization. These results reveal ∆21-121 EMCN as the minimal extracellular domain sufficient for VEGFR2-mediated endothelial function and demonstrate an important role for N-glycosylation in VEGFR2 interaction, internalization, and angiogenic activity.

scholarly journals Identification of distinct C3b and C4b recognition sites in the human C3b/C4b receptor (CR1, CD35) by deletion mutagenesis.

1988 ◽  
Vol 168 (5) ◽  
pp. 1699-1717 ◽  
Author(s):  
L B Klickstein ◽  
T J Bartow ◽  
V Miletic ◽  
L D Rabson ◽  
J A Smith ◽  
...  
Keyword(s):  
Amino Acid ◽  
Transmembrane Domain ◽  
Extracellular Domain ◽  
Cdna Clones ◽  
Alternative Pathways ◽  
Cos Cells ◽  
Short Consensus Repeats ◽  
Sds Page ◽  
Single Construct ◽  
A Site

Complementary DNA clones encoding the NH2-terminal region of human CR1 have been isolated and sequenced. The deduced complete amino acid sequence of the F allotype of human CR1 contains 2,039 residues, including a 41-residue signal peptide, an extracellular domain of 1,930 residues, a 25-amino acid transmembrane domain, and a 43-amino acid cytoplasmic region. The extracellular domain is composed exclusively of 30 short consensus repeats (SCRs), characteristic of the family of C3/C4-binding proteins. The 28 NH2-terminal SCRs are organized as four long homologous repeats (LHRs) of seven SCRs each. The newly sequenced LHR, LHR-A, is 61% identical to LHR-B in the NH2-terminal two SCRs and greater than 99% identical in the COOH-terminal five SCRs. Eight cDNA clones were spliced to form a single construct, piABCD, that contained the entire CR1 coding sequence downstream of a cytomegalovirus promoter. COS cells transfected with piABCD transiently expressed recombinant CR1 that comigrated with the F allotype of erythrocyte CR1 on SDS-PAGE and that mediated rosette formation with sheep erythrocytes bearing C4b and C3b. Recombinant CR1 also had factor I-cofactor activity for cleavage of C3(ma). Analyses of six deletion mutants expressed in COS cells indicated that the NH2-terminal two SCRs of LHR-A contained a site determining C4 specificity and the NH2-terminal two SCRs of LHR-B and -C each had a site determining C3 specificity. The presence of these three distinct sites in CR1 may enable the receptor to interact multivalently with C4b/C3b and C3b/C3b complexes generated during activation of the classical and alternative pathways.

scholarly journals Deglycosylation, processing and crystallization of human testis angiotensin-converting enzyme

2003 ◽  
Vol 371 (2) ◽  
pp. 437-442 ◽  
Author(s):  
Kerry GORDON ◽  
Pierre REDELINGHUYS ◽  
Sylva L.U. SCHWAGER ◽  
Mario R.W. EHLERS ◽  
Anastassios C. PAPAGEORGIOU ◽  
...  
Keyword(s):  
Protein A ◽  
Integral Membrane Protein ◽  
Native Enzyme ◽  
Human Testis ◽  
Type I ◽  
Converting Enzyme ◽  
Intracellular Degradation ◽  
Glycosylation Sites ◽  
Cell Dimensions ◽  
Necessary And Sufficient

Angiotensin I-converting enzyme (ACE) is a highly glycosylated type I integral membrane protein. A series of underglycosylated testicular ACE (tACE) glycoforms, lacking between one and five N-linked glycosylation sites, were used to assess the role of glycosylation in tACE processing, crystallization and enzyme activity. Whereas underglycosylated glycoforms showed differences in expression and processing, their kinetic parameters were similar to that of native tACE. N-glycosylation of Asn-72 or Asn-109 was necessary and sufficient for the production of enzymically active tACE but glycosylation of Asn-90 alone resulted in rapid intracellular degradation. All mutants showed similar levels of phorbol ester stimulation and were solubilized at the same juxtamembrane cleavage site as the native enzyme. Two mutants, tACEΔ36-g1234 and -g13, were successfully crystallized, diffracting to 2.8 and 3.0Å resolution respectively. Furthermore, a truncated, soluble tACE (tACEΔ36NJ), expressed in the presence of the glucosidase-I inhibitor N-butyldeoxynojirimycin, retained the activity of the native enzyme and yielded crystals belonging to the orthorhombic P212121 space group (cell dimensions, a = 56.47Å, b = 84.90Å, c = 133.99Å, α = 90°, β = 90° and γ = 90°). These crystals diffracted to 2.0Å resolution. Thus underglycosylated human tACE mutants, lacking O-linked oligosaccharides and most N-linked oligosaccharides or with only simple N-linked oligosaccharides attached throughout the molecule, are suitable for X-ray diffraction studies.

scholarly journals Analysis of two cDNA clones encoding the B lymphocyte antigen CD20 (B1, Bp35), a type III integral membrane protein.

1988 ◽  
Vol 167 (6) ◽  
pp. 1975-1980 ◽  
Author(s):  
I Stamenkovic ◽  
B Seed
Keyword(s):  
Membrane Protein ◽  
Untranslated Region ◽  
B Lymphocyte ◽  
Integral Membrane Protein ◽  
Cdna Clones ◽  
Expression Library ◽  
Coding Sequences ◽  
Cos Cells ◽  
Cd20 Antigen ◽  
Cell Expression

Two cDNA clones encoding the pan-B cell CD20 antigen were isolated from a COS cell expression library. The two clones bear identical coding sequences and differ only in the length of the 3' untranslated region. The predicted CD20 sequence is 297 residues long and contains three hydrophobic domains, one of which is long enough to span the membrane twice. COS cells transfected with either CD20 clone express an immunoreactive protein of 33 kD.

scholarly journals Molecular cloning of syndecan, an integral membrane proteoglycan.

1989 ◽  
Vol 108 (4) ◽  
pp. 1547-1556 ◽  
Author(s):  
S Saunders ◽  
M Jalkanen ◽  
S O'Farrell ◽  
M Bernfield
Keyword(s):  
Cell Surface ◽  
Heparan Sulfate ◽  
Chondroitin Sulfate ◽  
Transmembrane Domain ◽  
Core Protein ◽  
Extracellular Domain ◽  
Cdna Clones ◽  
Type I ◽  
Attachment Sites ◽  
Sequence Characteristics

We describe cDNA clones for a cell surface proteoglycan that bears both heparan sulfate and chondroitin sulfate and that links the cytoskeleton to the interstitial matrix. The cDNA encodes a unique core protein of 32,868 D that contains several structural features consistent with its role as a glycosamino-glycan-containing matrix anchor. The sequence shows discrete cytoplasmic, transmembrane, and NH2-terminal extracellular domains, indicating that the molecule is a type I integral membrane protein. The cytoplasmic domain is small and similar in size but not in sequence to that of the beta-chain of various integrins. The extracellular domain contains a single dibasic sequence adjacent to the extracellular face of the transmembrane domain, potentially serving as the protease-susceptible site involved in release of this domain from the cell surface. The extracellular domain contains two distinct types of putative glycosaminoglycan attachment sites; one type shows sequence characteristics of the sites previously described for chondroitin sulfate attachment (Bourdon, M. A., T. Krusius, S. Campbell, N. B. Schwartz, and E. Ruoslahti. 1987. Proc. Natl. Acad. Sci. USA. 84:3194-3198), but the other type has newly identified sequence characteristics that potentially correspond to heparan sulfate attachment sites. The single N-linked sugar recognition sequence is within the putative chondroitin sulfate attachment sequence, suggesting asparagine glycosylation as a mechanism for regulating chondroitin sulfate chain addition. Both 5' and 3' regions of this cDNA have sequences substantially identical to analogous regions of the human insulin receptor cDNA: a 99-bp region spanning the 5' untranslated and initial coding sequences is 67% identical and a 35-bp region in the 3' untranslated region is 81% identical in sequence. mRNA expression is tissue specific; various epithelial tissues show the same two sizes of mRNA (2.6 and 3.4 kb); in the same relative abundance (3:1), the cerebrum shows a single 4.5-kb mRNA. This core protein cDNA describes a new class of molecule, an integral membrane proteoglycan, that we propose to name syndecan (from the Greek syndein, to bind together).

The Genetic Defect of Type I von Willebrand Disease “Vicenza” Is Linked to the von Willebrand Factor Gene

1993 ◽  
Vol 69 (02) ◽  
pp. 173-176 ◽  
Author(s):  
Anna M Randi ◽  
Elisabetta Sacchi ◽  
Gian Carlo Castaman ◽  
Francesco Rodeghiero ◽  
Pier Mannuccio Mannucci
Keyword(s):  
Von Willebrand Factor ◽  
Autosomal Dominant ◽  
Genetic Defect ◽  
Von Willebrand Disease ◽  
Type I ◽  
Bleeding Tendency ◽  
Factor Gene ◽  
Low Levels ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryType I von Willebrand disease (vWD) Vicenza is a rare variant with autosomal dominant transmission, characterized by the presence of supranormal von Willebrand factor (vWF) multimers in plasma, similar to those normally found in endothelial cells and megakaryocytes. The patients have very low levels of plasma vWF contrasting with a mild bleeding tendency. The pathophysiology of this subtype is still unknown. The presence of supranormal multimers in the patients’ plasma could be due to a mutation in the vWF molecule which affects post-translational processing, or to a defect in the cells’ processing machinery, independent of the vWF molecule. In order to determne if type I vWD Vicenza is linked to the vWF gene, we studied six polymorphic systems identified within the vWF gene in two apparently unrelated families with type I vWD Vicenza. The results of this study indicate a linkage between vWF gene and the type I vWD Vicenza trait. This strongly suggests that type I vWD Vicenza is due to a mutation in one of the vWF alleles, which results in an abnormal vWF molecule that is processed to a lesser extent than normal vWF.

scholarly journals Cloning and sequence analysis of cDNAs encoding the α1, α2 and α3 chains of mouse collagen VI

1993 ◽  
Vol 291 (3) ◽  
pp. 787-792 ◽  
Author(s):  
R Z Zhang ◽  
T C Pan ◽  
R Timpl ◽  
M L Chu
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequences ◽  
Untranslated Regions ◽  
Cdna Libraries ◽  
Cdna Clones ◽  
Collagen Vi ◽  
Central Segment ◽  
Glycosylation Sites ◽  
Key Features ◽  
Triple Helical Domain

cDNA clones encoding the alpha 1, alpha 2 and alpha 3 chains of mouse collagen VI have been isolated by screening cDNA libraries with the corresponding human probes. The composite cDNAs for the alpha 1, alpha 2, and alpha 3 chains are 2.5, 1.6 and 2.9 kb in size respectively. The alpha 1 and alpha 2 cDNAs encode the C-terminal portions of the chains as well as the entire 3′-untranslated regions, while the alpha 3 cDNAs encode a central segment of 959 amino acids flanking the triple-helical domain. The deduced amino acid sequences share 86-88% identity with the human counterparts and 67-73% identity with the chicken equivalents. Alignment of the deduced amino acid sequences of mouse, human and chicken collagens reveal that the key features of the protein, including the cysteine residues, imperfections in the Gly-Xaa-Xaa regions, Arg-Gly-Asp sequences and potential N-glycosylation sites, are mostly conserved.

Effects of Berberine on Expression of LOX-1 and SR-BI in Human Macrophage-Derived Foam Cells Induced by ox-LDL

2010 ◽  
Vol 38 (06) ◽  
pp. 1161-1169 ◽  
Author(s):  
Siming Guan ◽  
Bin Wang ◽  
Wei Li ◽  
Jinghuan Guan ◽  
Xin Fang
Keyword(s):  
Scavenger Receptor ◽  
Ldl Receptor ◽  
Foam Cells ◽  
Time Dependent ◽  
Human Macrophage ◽  
Type I ◽  
Dependent Manner ◽  
Atp Binding Cassette Transporter ◽  
Abca1 Expression ◽  
Class B

This study investigates the effects of beriberine on the expression of lectin-like ox-LDL receptor-1 (LOX-1), scavenger receptor A (SR-A), SR class B type I (SR-BI) and ATP-binding cassette transporter A1 (ABCA1) in human macrophage-derived foam cells induced by ox-LDL. Different concentrations of Berberine were co-cultured with THP-1 derived foam cells. The mRNA and protein expressions of LOX-1, SR-A, SR-BI and ABCA1 were determined by RT-PCR and Western blot analysis, respectively. Ox-LDL significantly increased the expression of LOX-1 and inhibited the expression of SR-BI in a dose- and time-dependent manner. Berberine significantly inhibited the effects of ox-LDL in a dose- and time-dependent manner. Moreover, ox-LDL significantly promoted ABCA1 expression. However, berberine had no effect on SR-A or ABCA1 expression. Berberine can inhibit the expression of LOX-1 and promote the expression of SR-BI in macrophage-derived foam cells. Therefore, berberine could be used to treat atherosclerotic diseases.

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