CD26/DPPIV Signal Transduction Function, but Not Proteolytic Activity, Is Directly Related to Its Expression Level on Human Th1 and Th2 Cell Lines as Detected with Living Cell Cytochemistry

CD26/DPPIV is a cell surface glycoprotein that functions both in signal transduction and as a proteolytic enzyme, dipeptidyl peptidase IV (DPPIV). To investigate how two separate functions of one molecule are regulated, we analyzed CD26 protein expression and DPPIV enzyme activity on living human T-helper 1 (Th1) and Th2 cells that express different levels of CD26/DPPIV. DPPIV activity was specifically determined with the synthetic fluorogenic substrate ala-pro-cresyl violet and CD26 protein expression was demonstrated with an FITC-conjugated CD26-specific antibody. Fluorescence of liberated cresyl violet (red) and FITC (green) was detected simultaneously on living T-cells using flow cytometry and spectrofluorometry. Th1 cells expressed three- to sixfold more CD26 protein than Th2 cells. The signal transduction function of the CD26/DPPIV complex, tested by measuring its co-stimulatory potential for proliferation, was directly related to the amount of CD26 protein at the cell surface. However, DPPIV activity was similar in both cell populations at physiological substrate concentrations because of differences in Km and Vmax values of DPPIV on Th1 and Th2 cells. Western blotting and zymography of Th1 and Th2 whole-cell lysates demonstrated similar patterns. This study shows that two functions of one molecule can be controlled differentially.

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Intercellular adhesion of rat hepatocytes. Identification of a cell surface glycoprotein involved in the initial adhesion process.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)34499-5 ◽

1982 ◽

Vol 257 (12) ◽

pp. 6788-6795 ◽

Cited By ~ 6

Author(s):

C Ocklind ◽

B Obrink

Keyword(s):

Cell Surface ◽

Rat Hepatocytes ◽

Intercellular Adhesion ◽

Surface Glycoprotein ◽

Cell Surface Glycoprotein ◽

Initial Adhesion ◽

A Cell ◽

Adhesion Process

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Cloning of the gene encoding TROP-2, a cell-surface glycoprotein expressed by human carcinomas

International Journal of Cancer ◽

10.1002/ijc.2910620520 ◽

1995 ◽

Vol 62 (5) ◽

pp. 610-618 ◽

Cited By ~ 67

Author(s):

Mara Fornaro ◽

Roberta Dell' Arciprete ◽

Manuela Stella ◽

Cecilia Bucci ◽

Michele Nutini ◽

...

Keyword(s):

Cell Surface ◽

Surface Glycoprotein ◽

Gene Encoding ◽

Cell Surface Glycoprotein ◽

Human Carcinomas ◽

A Cell

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ADAM23 is a cell-surface glycoprotein expressed by central nervous system neurons

Journal of Neuroscience Research ◽

10.1002/jnr.20320 ◽

2004 ◽

Vol 78 (5) ◽

pp. 647-658 ◽

Cited By ~ 20

Author(s):

Alexander P. Goldsmith ◽

Samuel J. Gossage ◽

Charles ffrench-Constant

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Cell Surface ◽

Surface Glycoprotein ◽

Cell Surface Glycoprotein ◽

A Cell

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Visualization of a cell surface glycoprotein, the retina cognin, on embryonic cells by immuno-latex labeling and scanning electron microscopy

Developmental Biology ◽

10.1016/0012-1606(79)90100-3 ◽

1979 ◽

Vol 72 (1) ◽

pp. 89-101 ◽

Cited By ~ 24

Author(s):

Y. Ben-Shaul ◽

R.E. Hausman ◽

A.A. Moscona

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Cell Surface ◽

Surface Glycoprotein ◽

Embryonic Cells ◽

Cell Surface Glycoprotein ◽

A Cell ◽

Scanning Electron

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AG alpha 1 is the structural gene for the Saccharomyces cerevisiae alpha-agglutinin, a cell surface glycoprotein involved in cell-cell interactions during mating.

Molecular and Cellular Biology ◽

10.1128/mcb.9.8.3155 ◽

1989 ◽

Vol 9 (8) ◽

pp. 3155-3165 ◽

Cited By ~ 109

Author(s):

P N Lipke ◽

D Wojciechowicz ◽

J Kurjan

Keyword(s):

Cell Surface ◽

Fusion Protein ◽

Structural Gene ◽

Signal Sequence ◽

Positive Control ◽

Complementation Group ◽

Surface Glycoprotein ◽

Cell Surface Glycoprotein ◽

Amino Terminal ◽

A Cell

We have cloned the alpha-agglutinin structural gene, AG alpha 1, by the isolation of alpha-specific agglutination-defective mutants, followed by isolation of a complementing plasmid. Independently isolated alpha-specific agglutination-defective mutations were in a single complementation group, consistent with biochemical results indicating that the alpha-agglutinin is composed of a single polypeptide. Mapping results suggested that the complementation group identified by these mutants is allelic to the ag alpha 1 mutation identified previously. Expression of AG alpha 1 RNA was alpha specific and inducible by a-factor. Sequences similar to the consensus sequences for positive control by MAT alpha 1 and pheromone induction were found upstream of the AG alpha 1 initiation codon. The AG alpha 1 gene could encode a 650-amino-acid protein with a putative signal sequence, 12 possible N-glycosylation sites, and a high proportion of serine and threonine residues, all of which are features expected for the alpha-agglutinin sequence. Disruption of the AG alpha 1 gene resulted in failure to express alpha-agglutinin and loss of cellular agglutinability in alpha cells. An Escherichia coli fusion protein containing 229 amino acids of the AG alpha 1 sequence was recognized by an anti-alpha-agglutinin antibody. In addition, the ability of this antibody to inhibit agglutination was prevented by this fusion protein. These results indicate that AG alpha 1 encodes alpha-agglutinin. Features of the AG alpha 1 gene product suggest that the amino-terminal half of the protein contains the a-agglutinin binding domain and that the carboxy-terminal half contains a cell surface localization domain, possibly including a glycosyl phosphatidylinositol anchor.

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Differentiation defective mutants of skeletal myoblasts altered in a gelatin-binding glycoprotein

Biochemistry and Cell Biology ◽

10.1139/o87-100 ◽

1987 ◽

Vol 65 (9) ◽

pp. 767-775 ◽

Cited By ~ 25

Author(s):

George A. Cates ◽

Devki Nandan ◽

Anne M. Brickenden ◽

Bishnu D. Sanwal

Keyword(s):

Cell Surface ◽

Molecular Mass ◽

Surface Glycoprotein ◽

Myoblast Differentiation ◽

Wild Type ◽

Cell Surface Glycoprotein ◽

Adhesion Properties ◽

Normal Rat ◽

A Cell ◽

Myoblast Cell

We have previously described a myoblast cell surface glycoprotein of the molecular mass 46 000 (gp46), which is associated with myoblast differentiation. In this report we demonstrate that gp46 binds specifically to gelatin-Sepharose and in this respect is similar to a glycoprotein of the molecular mass 47 000, which has earlier been described as a cell surface localized protein in mouse parietal endoderm cells and in chick embryo fibroblasts. To ascertain the relationship of gp46 to myoblast differentiation, wild-type L6 myoblasts, as well as two concanavalin A (ConA) resistant, differentiation-negative, myoblast mutants (D-1 and C-8), were examined for gp46 expression. In the mutant designated D-1, which has a defect in dolichol mannosyl transferase, both mannose incorporation into gp46 and ConA binding to gp46 was reduced compared with L6, without markedly affecting the gelatin adhesion properties of gp46. Western blotting with a monoclonal antibody against gp46 was used to show that the expression of gp46 was normal in D-1 but was reduced in mutant C-8 compared with L6. Reduction occurred both in the plasma membrane and endoplasmic reticulum fractions of C-8 compared with wild-type L6. In L6 myoblasts, the expression of gp46 remained constant during myoblast replication and fusion but decreased markedly postfusion. In the nonfusing myoblast mutants D-1 and C-8 and in wild-type L6 cells that were prevented from fusing by treatment with 5-bromo-2′-deoxyuridine, the expression of gp46 remained invariant. We suggest that collagen interactions, mediated by gp46, are important for normal rat skeletal muscle differentiation.

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