scholarly journals A polymorphic, prespore-specific cell surface glycoprotein is present in the extracellular matrix of Dictyostelium discoideum.

1985 ◽  
Vol 5 (10) ◽  
pp. 2559-2566 ◽  
Author(s):  
W N Grant ◽  
D L Welker ◽  
K L Williams
Keyword(s):  
Extracellular Matrix ◽  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Genetic Relationships ◽  
Specific Protein ◽  
Surface Glycoprotein ◽  
Specific Cell ◽  
Developmentally Regulated ◽  
Cell Surface Glycoprotein ◽  
Specific Cell Surface

Polymorphisms of a major developmentally regulated prespore-specific protein (PsA) in Dictyostelium discoideum slugs are described. These polymorphisms allowed discrimination between PsA (found on the cell surface and in the extracellular matrix) and a similar extracellular but nonpolymorphic protein, ShA. The two proteins were also distinguished by their differing reactivities with a range of monoclonal antibodies and by their sensitivity to release from the sheath with cellulase. The results are discussed in terms of the molecular and genetic relationships between the cell surface and the extracellular matrix during development.

A polymorphic, prespore-specific cell surface glycoprotein is present in the extracellular matrix of Dictyostelium discoideum

1985 ◽  
Vol 5 (10) ◽  
pp. 2559-2566
Author(s):  
W N Grant ◽  
D L Welker ◽  
K L Williams
Keyword(s):  
Extracellular Matrix ◽  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Genetic Relationships ◽  
Specific Protein ◽  
Surface Glycoprotein ◽  
Specific Cell ◽  
Developmentally Regulated ◽  
Cell Surface Glycoprotein ◽  
Specific Cell Surface

Polymorphisms of a major developmentally regulated prespore-specific protein (PsA) in Dictyostelium discoideum slugs are described. These polymorphisms allowed discrimination between PsA (found on the cell surface and in the extracellular matrix) and a similar extracellular but nonpolymorphic protein, ShA. The two proteins were also distinguished by their differing reactivities with a range of monoclonal antibodies and by their sensitivity to release from the sheath with cellulase. The results are discussed in terms of the molecular and genetic relationships between the cell surface and the extracellular matrix during development.

scholarly journals The eosinophil-specific cell surface antigen, EOS47, is a chicken homologue of the oncofetal antigen melanotransferrin

Blood ◽  
1996 ◽  
Vol 87 (4) ◽  
pp. 1343-1352 ◽  
Author(s):  
KM McNagny ◽  
F Rossi ◽  
G Smith ◽  
T Graf
Keyword(s):  
Bone Marrow ◽  
Cell Surface ◽  
Peripheral Blood ◽  
Tertiary Structure ◽  
Surface Glycoprotein ◽  
Peptide Sequence ◽  
Sequence Information ◽  
Specific Cell ◽  
Specific Marker ◽  
Cell Surface Glycoprotein

The EOS47 antigen is a 100-kD cell surface glycoprotein selectively expressed by avian retrovirus-transformed eosinophils and their precursors. We have purified the EOS47 protein to homogeneity and used peptide sequence information to clone EOS47-encoding cDNAs. The open reading frames from these cDNAs predict a 738 amino acid protein with homology to human melanotransferrin, a membrane-found, transferrin-like protein that is expressed at high levels by a subset of melanomas, tumor cell lines, fetal intestine, and liver, but not by most normal adult tissues. The predicted protein sequence of EOS47 displays a 61% sequence identity with melanotransferrin and conservation of all 28 cysteine residues, indicating a similar tertiary structure. The finding that EOS47 lacks several of the iron-coordinating amino acids present in all transferrins suggests that it may be impaired in its ability to bind iron. In nonhematopoietic tissues, EOS47 is expressed at high levels by epithelial brush borders of small intestine and kidney and at lower levels by cells lining the sinusoids of the liver. Within hematopoietic tissues, EOS47 is restricted to a subpopulation of cells (1% to 5%) in bone marrow and early spleen and fluorescence-activated cell sorting of EOS47+ cells leads to a dramatic ( > 30-fold) enrichment of peroxidase+ eosinophils. In contrast, peripheral blood eosinophils are EOS47-, suggesting that the antigen is expressed by newly formed eosinophils and that expression ceases shortly before these cells emigrate from the bone marrow into the peripheral blood. Our results show that melanotransferrin is a stage-specific marker of eosinophils and should be useful for their isolation and further characterization.

scholarly journals A stoichiometric complex of neurexins and dystroglycan in brain

2001 ◽  
Vol 154 (2) ◽  
pp. 435-446 ◽  
Author(s):  
Shuzo Sugita ◽  
Fumiaki Saito ◽  
Jiong Tang ◽  
Jakob Satz ◽  
Kevin Campbell ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Surface ◽  
Surface Protein ◽  
Surface Proteins ◽  
Sex Hormone Binding Globulin ◽  
Muscular Dystrophies ◽  
Specific Cell ◽  
Mediate Cell Adhesion ◽  
Mediate Cell ◽  
Specific Cell Surface

In nonneuronal cells, the cell surface protein dystroglycan links the intracellular cytoskeleton (via dystrophin or utrophin) to the extracellular matrix (via laminin, agrin, or perlecan). Impairment of this linkage is instrumental in the pathogenesis of muscular dystrophies. In brain, dystroglycan and dystrophin are expressed on neurons and astrocytes, and some muscular dystrophies cause cognitive dysfunction; however, no extracellular binding partner for neuronal dystroglycan is known. Regular components of the extracellular matrix, such as laminin, agrin, and perlecan, are not abundant in brain except in the perivascular space that is contacted by astrocytes but not by neurons, suggesting that other ligands for neuronal dystroglycan must exist. We have now identified α- and β-neurexins, polymorphic neuron-specific cell surface proteins, as neuronal dystroglycan receptors. The extracellular sequences of α- and β-neurexins are largely composed of laminin-neurexin–sex hormone–binding globulin (LNS)/laminin G domains, which are also found in laminin, agrin, and perlecan, that are dystroglycan ligands. Dystroglycan binds specifically to a subset of the LNS domains of neurexins in a tight interaction that requires glycosylation of dystroglycan and is regulated by alternative splicing of neurexins. Neurexins are receptors for the excitatory neurotoxin α-latrotoxin; this toxin competes with dystroglycan for binding, suggesting overlapping binding sites on neurexins for dystroglycan and α-latrotoxin. Our data indicate that dystroglycan is a physiological ligand for neurexins and that neurexins' tightly regulated interaction could mediate cell adhesion between brain cells.

scholarly journals Size polymorphisms due to changes in the number of O-glycosylated tandem repeats in the Dictyostelium discoideum glycoprotein PsA.

Genetics ◽  
1992 ◽  
Vol 130 (4) ◽  
pp. 749-756
Author(s):  
A A Gooley ◽  
R Marshchalek ◽  
K L Williams
Keyword(s):  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Tandem Repeats ◽  
Allelic Variation ◽  
Surface Glycoprotein ◽  
Crossing Over ◽  
Globular Domain ◽  
Cell Surface Glycoprotein ◽  
Ancestral Gene ◽  
Repeat Domain

Abstract The molecular weight polymorphism in the Dictyostelium discoideum cell surface glycoprotein PsA is due to incremental copies of an O-glycosylated tandem tetrapeptide repeat. Allelic variation at the pspA locus results in a PsA glycoprotein with three, four or five tandem copies of Pro-Thr-Val-Thr. The simplest explanation for the origin of this polymorphism is an unequal crossing over event in the ancestral gene containing four copies. Each Thr in the tandem repeat is substituted with carbohydrate, which is completely absent from PsA in strains carrying a glycosylation defective modB mutation. Glycosylated tandem repeats appear to be a common feature of cell surface glycoproteins which are characterized by short domains rich in Pro and Thr or Ser. It is probable that the glycosylated repeat domain acts as a "spacer" peptide that projects the globular domain above the glycocalyx.

scholarly journals EMA: A developmentally regulated cell-surface glycoprotein of CNS neurons that is concentrated at the leading edge of growth cones

1992 ◽  
Vol 194 (4) ◽  
pp. 311-325 ◽  
Author(s):  
Nikki L. Baumrind ◽  
David Parkinson ◽  
Denise B. Wayne ◽  
John E. Heuser ◽  
Alan L. Pearlman
Keyword(s):  
Cell Surface ◽  
Leading Edge ◽  
Growth Cones ◽  
Surface Glycoprotein ◽  
Developmentally Regulated ◽  
Cell Surface Glycoprotein ◽  
Cns Neurons
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