scholarly journals Molecular cloning and expression of the cDNA for alpha 3 subunit of human alpha 3 beta 1 (VLA-3), an integrin receptor for fibronectin, laminin, and collagen.

1991 ◽  
Vol 115 (1) ◽  
pp. 257-266 ◽  
Author(s):  
Y Takada ◽  
E Murphy ◽  
P Pil ◽  
C Chen ◽  
M H Ginsberg ◽  
...  

alpha 3 beta 1 (VLA-3), a member of the integrin family of cell adhesion receptors, may function as a receptor for fibronectin, laminin, and collagen. A partial cDNA clone (2.4 kb) for the human alpha 3 subunit was selected from an endothelial cell lambda gt11 cDNA library by specific antibody screening. Several overlapping cDNA clones were subsequently obtained, of a total length of 4.6 kb from various cDNA libraries. The reconstructed alpha 3 cDNA was expressed on the surface of chinese hamster ovary cells as detected by an alpha 3-specific mAb after transfection, suggesting that the cDNA is authentic. Within this sequence was an open reading frame, encoding for 1,051 amino acids, including a signal peptide of 32 residues, a long extracellular domain (959 residues), a transmembrane domain (28 residues), and a short cytoplasmic segment (32 residues). Overall, the alpha 3 amino acid sequence was 25-37% similar to the other integrin alpha subunits that are cleaved, with most similarity to the alpha 6 sequence (37%), and less similarity to those alpha subunits that have I domains (15-20%, excluding the I domain sequence itself). Features most like those in other alpha subunits are (a) the positions of 18/19 cysteine residues, (b) three potential metal binding domains of the general structure DX(D/N)X(D/N)GXXD, and (c) the predicted transmembrane domain. The mass of alpha 3 calculated from its amino acid sequence is 113,505. The human alpha 3 sequence was 89% identical to hamster galactoprotein b3, and 70% similar to the chicken CSAT antigen band 2 protein partial sequence, suggesting that these two polypeptides are homologues of human alpha 3.

1989 ◽  
Vol 109 (1) ◽  
pp. 397-407 ◽  
Author(s):  
Y Takada ◽  
M E Hemler

VLA-2 (also called gpIa/IIa on platelets) is a collagen receptor with a unique alpha subunit and a beta subunit common to other adhesion receptors in the VLA/integrin family. Multiple cDNA clones for the human VLA-2 alpha 2 subunit have been selected from a lambda gtll library by specific antibody screening. The 5,374-bp nucleotide sequence encoded for 1,181 amino acids, including a signal peptide of 29 amino acids followed by a long extracellular domain (1,103 amino acids), a transmembrane domain, and a short cytoplasmic segment (22 amino acids). Direct sequencing of purified alpha 2 protein confirmed the identity of the 15 NH2-terminal amino acids. Overall, the alpha 2 amino acid sequence was 18-25% similar to the sequences known for other integrin alpha subunits. In particular, the alpha 2 sequence matched other integrin alpha chains in (a) the positions of 17 of its 20 cysteine residues; (b) the presence of three metal-binding domains of the general structure DXDXDGXXD; and (c) the transmembrane domain sequence. In addition, the alpha 2 sequence has a 191-amino acid insert (called the I-domain), previously found only in leukocyte integrins of the beta 2 integrin family. The alpha 2 I-domain was 23-41% similar to domains in cartilage matrix protein and von Willebrand factor, which are perhaps associated with collagen binding. The NH2-terminal sequence reported here for alpha 2 does not match the previously reported alpha 2 NH2-terminal sequence (Takada, Y., J. L. Strominger, and M. E. Hemler. 1987. Proc. Natl. Acad. Sci. USA. 84:3239-3243). Resolution of this discrepancy suggests that there may be another VLA heterodimer that resembles VLA-2 in size but has a different amino acid sequence.


1992 ◽  
Vol 12 (12) ◽  
pp. 5600-5609 ◽  
Author(s):  
L W Burrus ◽  
M E Zuber ◽  
B A Lueddecke ◽  
B B Olwin

The fibroblast growth factor (FGF) family consists of seven members whose activities are thought to be mediated by multiple receptors. Here we describe the cDNA cloning, expression, and characterization of a cysteine-rich FGF receptor (CFR) that is distinct from previously identified FGF receptors. The deduced amino acid sequence for CFR suggests that it is an integral membrane protein containing a large extracellular domain comprising 16 cysteine-rich repeated units and an intracellular domain of 13 amino acids. No reported sequences exhibit significant homologies to either the repeated extracellular motif or to the entire CFR amino acid sequence. Several CFR transcripts are present in embryonic chick tissue, suggesting that CFR undergoes alternate mRNA splicing or that related genes are present. Chinese hamster ovary cells transfected with the CFR cDNA express a 150-kDa polypeptide that binds FGF-1, FGF-2, and FGF-4 but does not bind several non-FGF family members. The high degree of evolutionary conservation among vertebrate CFRs and its ability to bind three different FGFs with high affinity suggest that this unique receptor plays an important role in FGF biology.


Blood ◽  
2003 ◽  
Vol 101 (2) ◽  
pp. 552-559 ◽  
Author(s):  
Lijun Xia ◽  
Vishwanath Ramachandran ◽  
J. Michael McDaniel ◽  
Kiem N. Nguyen ◽  
Richard D. Cummings ◽  
...  

P-selectin binds to the N-terminal region of human P-selectin glycoprotein ligand-1 (PSGL-1). For optimal binding, this region requires sulfation on 3 tyrosines and specific core-2O-glycosylation on a threonine. P-selectin is also thought to bind to the N terminus of murine PSGL-1, although it has a very different amino acid sequence than human PSGL-1. Murine PSGL-1 has potential sites for sulfation at Tyr13 and Tyr15 and for O-glycosylation at Thr14 and Thr17. We expressed murine PSGL-1 or constructs with substitutions of these residues in transfected Chinese hamster ovary cells that coexpressed the glycosyltransferases required for binding to P-selectin. The cells were assayed for binding to fluid-phase P-selectin and for tethering and rolling on P-selectin under flow. In both assays, substitution of Tyr13 or Thr17 markedly diminished, but did not eliminate, binding to P-selectin. In contrast, substitution of Tyr15 or Thr14 did not affect binding. Substitution of all 4 residues eliminated binding. Treatment of cells with chlorate, an inhibitor of sulfation, markedly reduced binding of wild-type PSGL-1 to P-selectin but did not further decrease binding of PSGL-1 with substitutions of both tyrosines. These data suggest that sulfation of Tyr13 andO-glycosylation of Thr17 are necessary for murine PSGL-1 to bind optimally to P-selectin. Because it uses only one tyrosine, murine PSGL-1 may rely more on other peptide components andO-glycosylation to bind to P-selectin than does human PSGL-1.


1997 ◽  
Vol 323 (2) ◽  
pp. 525-531 ◽  
Author(s):  
Susanna T. ENGBERG ◽  
Toshifumi AOYAMA ◽  
Stefan E. H. ALEXSON ◽  
Takashi HASHIMOTO ◽  
L. Thomas SVENSSON

We have isolated and cloned a cDNA that codes for one of the peroxisome proliferator-induced acyl-CoA thioesterases of rat liver. The deduced amino acid sequence corresponds to the major induced isoform in cytosol. Analysis and comparison of the deduced amino acid sequence with the established consensus sequences suggested that this enzyme represents a novel kind of esterase with an incomplete lipase serine active site motif. Analyses of mRNA and its expression indicated that the enzyme is significantly expressed in liver only after peroxisome proliferator treatment, but isoenzymes are constitutively expressed at high levels in testis and brain. The reported cDNA sequence is highly homologous to the recently cloned brain acyl-CoA thioesterase [Broustas, Larkins, Uhler and Hajra (1996) J. Biol. Chem. 271, 10470–10476], but subtle differences throughout the sequence, and distinct differences close to the resulting C-termini, suggest that they are different enzymes, regulated in different manners. A full-length cDNA clone was expressed in Chinese hamster ovary cells and the expressed enzyme was characterized. The palmitoyl-CoA hydrolysing activity (Vmax) was induced approx. 9-fold to 1 μmol/min per mg of cell protein, which was estimated to correspond to a specific activity of 250 μmol/min per mg of cDNA-expressed enzyme. Both the specific activity and the acyl-CoA chain length specificity were very similar to those of the purified rat liver enzyme.


1992 ◽  
Vol 12 (12) ◽  
pp. 5600-5609
Author(s):  
L W Burrus ◽  
M E Zuber ◽  
B A Lueddecke ◽  
B B Olwin

The fibroblast growth factor (FGF) family consists of seven members whose activities are thought to be mediated by multiple receptors. Here we describe the cDNA cloning, expression, and characterization of a cysteine-rich FGF receptor (CFR) that is distinct from previously identified FGF receptors. The deduced amino acid sequence for CFR suggests that it is an integral membrane protein containing a large extracellular domain comprising 16 cysteine-rich repeated units and an intracellular domain of 13 amino acids. No reported sequences exhibit significant homologies to either the repeated extracellular motif or to the entire CFR amino acid sequence. Several CFR transcripts are present in embryonic chick tissue, suggesting that CFR undergoes alternate mRNA splicing or that related genes are present. Chinese hamster ovary cells transfected with the CFR cDNA express a 150-kDa polypeptide that binds FGF-1, FGF-2, and FGF-4 but does not bind several non-FGF family members. The high degree of evolutionary conservation among vertebrate CFRs and its ability to bind three different FGFs with high affinity suggest that this unique receptor plays an important role in FGF biology.


1992 ◽  
Vol 175 (2) ◽  
pp. 341-351 ◽  
Author(s):  
Y Murata ◽  
S Takaki ◽  
M Migita ◽  
Y Kikuchi ◽  
A Tominaga ◽  
...  

Human interleukin 5 (IL-5) plays an important role in proliferation and differentiation of human eosinophils. We report the isolation of cDNA clones from cDNA libraries of human eosinophils by using murine IL-5 receptor alpha chain cDNA as a probe. Analysis of the predicted amino acid sequence indicated that the human IL-5 receptor has approximately 70% amino acid sequence homology with the murine IL-5 receptor and retains features common to the cytokine receptor superfamily. One cDNA clone encodes a glycoprotein of 420 amino acids (Mr 47,670) with an NH2-terminal hydrophobic region (20 amino acids), a glycosylated extracellular domain (324 amino acids), a transmembrane domain (21 amino acids), and a cytoplasmic domain (55 amino acids). Another cDNA encodes only the extracellular domain of this receptor molecule. Other cDNA clones encode molecules having diversified cytoplasmic domains. COS7 cells transfected with the cDNA expressed a approximately 60-kD protein and bound IL-5 with a single class of affinity (Kd = 250-590 pM). The Kd values were similar to that observed in normal human eosinophils. In contrast to the murine 60-kD alpha chain, which binds IL-5 with low affinity (Kd = approximately 10 nM), the human alpha chain homologue can bind IL-5 with much higher affinity by itself. RNA blot analysis of human cells demonstrated two transcripts (approximately 5.3 and 1.4 kb). Both of them were expressed in normal human eosinophils and in erythroleukemic cell line TF-1, which responds to IL-5. The human IL-5 receptor characterized in this paper is essential for signal transduction, because expression of this molecule in murine IL-3-dependent cell line FDC-P1 allowed these cells to proliferate in response to IL-5.


1993 ◽  
Vol 290 (3) ◽  
pp. 765-770 ◽  
Author(s):  
D H Maurice ◽  
G L Waldo ◽  
A J Morris ◽  
R A Nicholas ◽  
T K Harden

A 43 kDa phospholipase C-activating protein has been purified previously from turkey erythrocytes and shown to express immunological properties expected of that of the Gq family of G-protein alpha-subunits [Waldo, Boyer, Morris and Harden (1991) J. Biol. Chem. 266, 14217-14225]. Internal amino acid sequence has now been obtained from this protein which shares 50-100% sequence identity with sequences encoded by mammalian G alpha 11 and G alpha q cDNAs. To identify the purified protein unambiguously, it was necessary to compare its amino acid sequence with the sequence encoded by avian G-protein alpha-subunit cDNA. As such, mouse G alpha q was used as a probe to screen turkey brain and fetal-turkey blood cDNA libraries. A full-length cDNA was identified that encodes avian G alpha 11, on the basis of its 96-98% amino acid identity with mammalian G alpha 11. All eight peptides sequenced from the turkey erythrocyte phospholipase C-activating protein are completely contained within the deduced amino acid sequence of the avian G alpha 11 cDNA. Expression of this cDNA in Sf9 cells by using a baculovirus expression system resulted in the production of a 43 kDa protein that reacts strongly with antisera to the Gq family of G-protein alpha-subunits and activated purified avian phospholipase C in an AlF4(-)-dependent manner. Taken together, these results unambiguously identify the protein purified from turkey erythrocytes, on the basis of its capacity to activate avian phospholipase C, as G alpha 11.


1993 ◽  
Vol 70 (03) ◽  
pp. 418-422 ◽  
Author(s):  
Masaharu Aritomi ◽  
Naoko Watanabe ◽  
Rika Ohishi ◽  
Komakazu Gomi ◽  
Takao Kiyota ◽  
...  

SummaryRecombinant human soluble thrombomodulin (rhs-TM), having no transmembrane domain or chondroitin sulfate, was expressed in Chinese hamster ovary cells. Interactions between rhs-TM, thrombin (Th), protein C (PC) and antithrombin III (ATIII) were studied. Equilibrium between rhs-TM and Th had no detectable time lag in clotting inhibition (K d = 26 nM) or PC activation (K d = 22 nM), while ATIII inhibited Th at a bimolecular rate constant = 5,200 M-1s-1 (K d <0.2 nM). A mixture of ATIII, Th and rhs-TM showed that ATIII reacted with Th slower than rhs-TM, whose presence did not affect the reaction between ATIII and Th. In a mixture of rhs-TM, ATIII and PC, the repeated addition of Th caused the repeated activation of PC; which was consistent with the Simulation based on the assumption that rhs-TM is recycled as a Th cofactor. From these results, we concluded that upon inhibition of the rhs-TM-Th complex by ATIII, rhs-TM is released to recombine with free Th and begins to activate PC, while the Th-ATIII complex does not affect rhs-TM-Th equilibrium.


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