The Experts below are selected from a list of 99 Experts worldwide ranked by ideXlab platform

Jose Luis Millan - One of the best experts on this subject based on the ideXlab platform.

Torgny Stigbrand - One of the best experts on this subject based on the ideXlab platform.

  • Structural and functional analysis of a non-catalytic binding site in human Placental Alkaline Phosphatase
    2009
    Co-Authors: Alexey Kozlenkov, Torgny Stigbrand, Jose Luis Millan, Karan S. Crilly, Paola Llinas, André Ménez, Enrico A. Stura, Zoltan Kiss
    Abstract:

    Structural and functional analysis of a non-catalytic binding site in human Placental Alkaline Phosphatase

  • Placental Alkaline Phosphatase has a binding site for the human immunoglobulin-G Fc portion.
    European journal of biochemistry, 1992
    Co-Authors: Ricardo Makiya, Torgny Stigbrand
    Abstract:

    Affinity chromatography of human plasma on Placental-Alkaline-Phosphatase–Sepharose columns (Placental Alkaline Phosphatase, PLAP) yielded consistently a pure protein which was identified as IgG on the basis of electrophoretical and immunological comparisons with authentic human IgG. SDS/PAGE of the protein revealed, under reducing conditions, two polypeptides of 55 kDa and 25 kDa. The N-terminal amino acid sequence (12 residues) of the 55-kDa subunit presented high similarity (83–100%) with known sequences of immunoglobulin gamma chains. The IgG binds by its Fc portion to a fully exposed domain in the plasma-membrane-anchored PLAP. Scatchard analysis of the interaction gave a dissociation constant of 3.68 γM, a value close to those found for haematopoietic cells and syncytiotrophoblast Fc receptors. The latter was affinity purified from human placenta as the major IgG-binding component and presented cross-immunoreactivity with anti-PLAP antibodies, indicating that PLAP and the putative Placental Fc receptor could be identical molecules.

  • Placental Alkaline Phosphatase, a GPI-anchored protein, is clustered in clathrin-coated vesicles.
    Biochemical and biophysical research communications, 1992
    Co-Authors: Ricardo Makiya, Lars-eric Thornell, Torgny Stigbrand
    Abstract:

    Abstract Pure clathrin-coated vesicles were prepared from a fresh human placenta. The analysis of their content revealed the presence of transferrin, low density lipoproteins, IgG and Placental Alkaline Phosphatase. Since the latter is a membrane protein anchored by a glycan-phosphatidyl inositol (GPI) moiety, its presence in coated vesicles was unexpected. Placental Alkaline Phosphatase is neither adsorbed to the surface of the vesicles, nor appearing due to plasma membrane contaminants, but is located in the lumen of the vesicles. The presence of Alkaline Phosphatase in coated vesicles strenghthens its postulated physiological role in the transcytosis of IgG molecules in placenta.

  • Placental Alkaline Phosphatase is related to human IgG internalization in HEp2 cells.
    Biochemical and biophysical research communications, 1992
    Co-Authors: Ricardo Makiya, Torgny Stigbrand
    Abstract:

    Abstract The biological function(s) of Placental Alkaline Phosphatase has not yet been unraveled. The low catalytic activity of the enzyme at physiological pH, and the lack of “natural substrates”, bring about the necessity of a more structure-related conception of its role. We have observed an interaction between Placental Alkaline Phosphatase and human IgG. In this report we show that this isozyme is the major membrane protein able to bind IgG in a IgG-internalizing cell line (HEp2). Pretreatment of these cells with Fab fragments of anti Placental Alkaline Phosphatase antibodies blocks the internalization of IgG without perturbing the endocytosis of other ligands. Our results indicate that Placental Alkaline Phosphatase has the ability not only to bind human IgG, but also to promote its internalization in HEp2 cells.

  • CA125 and Placental Alkaline Phosphatase as serum tumor markers in epithelial ovarian carcinoma
    Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine, 1992
    Co-Authors: I Vergote, Torgny Stigbrand, Vera M. Abeler, Ole P. Børmer, Claes G. Tropé, K Nustad
    Abstract:

    Placental Alkaline Phosphatase (PLAP) was measured by an immunoradiometric assay using the monoclonal antibody C2 (PLAP-C2). Serum samples of 135 patients with epithelial ovarian cancer were analyzed,

Anna Kelsey - One of the best experts on this subject based on the ideXlab platform.

  • Germ cell expression of Placental Alkaline Phosphatase in male pseudohermaphroditism
    Histopathology, 1991
    Co-Authors: G.r. Armstrong, C.h. Buckley, Anna Kelsey
    Abstract:

    We have reviewed testes removed from 14 individuals with male pseudohermaphroditism (13 with androgen insensitivity and one with 17 α-hydroxylase deficiency) and have studied staining for Placental Alkaline Phosphatase in germ cells. Placental Alkaline Phosphatase positivity was identified in fetal and premature neonatal controls but not in cryptorchid males or normal autopsy control material from boys older than 6 months. It was present in autopsy testes younger than 6 months and cases of androgen insensitivity in boys younger than 8 months, suggesting immaturity. It was also expressed in two patients with male pseudohermaphroditism aged 5 years and 14 years, both of whom had intra-tubular germ cell neoplasia by morphological criteria. Our study confirms the use of Placental Alkaline phospatase as a marker of germ cell neoplasia in this specific group who are at high risk of malignancy.

G.r. Armstrong - One of the best experts on this subject based on the ideXlab platform.

  • Germ cell expression of Placental Alkaline Phosphatase in male pseudohermaphroditism
    Histopathology, 1991
    Co-Authors: G.r. Armstrong, C.h. Buckley, Anna Kelsey
    Abstract:

    We have reviewed testes removed from 14 individuals with male pseudohermaphroditism (13 with androgen insensitivity and one with 17 α-hydroxylase deficiency) and have studied staining for Placental Alkaline Phosphatase in germ cells. Placental Alkaline Phosphatase positivity was identified in fetal and premature neonatal controls but not in cryptorchid males or normal autopsy control material from boys older than 6 months. It was present in autopsy testes younger than 6 months and cases of androgen insensitivity in boys younger than 8 months, suggesting immaturity. It was also expressed in two patients with male pseudohermaphroditism aged 5 years and 14 years, both of whom had intra-tubular germ cell neoplasia by morphological criteria. Our study confirms the use of Placental Alkaline phospatase as a marker of germ cell neoplasia in this specific group who are at high risk of malignancy.

Ricardo Makiya - One of the best experts on this subject based on the ideXlab platform.

  • Placental Alkaline Phosphatase has a binding site for the human immunoglobulin-G Fc portion.
    European journal of biochemistry, 1992
    Co-Authors: Ricardo Makiya, Torgny Stigbrand
    Abstract:

    Affinity chromatography of human plasma on Placental-Alkaline-Phosphatase–Sepharose columns (Placental Alkaline Phosphatase, PLAP) yielded consistently a pure protein which was identified as IgG on the basis of electrophoretical and immunological comparisons with authentic human IgG. SDS/PAGE of the protein revealed, under reducing conditions, two polypeptides of 55 kDa and 25 kDa. The N-terminal amino acid sequence (12 residues) of the 55-kDa subunit presented high similarity (83–100%) with known sequences of immunoglobulin gamma chains. The IgG binds by its Fc portion to a fully exposed domain in the plasma-membrane-anchored PLAP. Scatchard analysis of the interaction gave a dissociation constant of 3.68 γM, a value close to those found for haematopoietic cells and syncytiotrophoblast Fc receptors. The latter was affinity purified from human placenta as the major IgG-binding component and presented cross-immunoreactivity with anti-PLAP antibodies, indicating that PLAP and the putative Placental Fc receptor could be identical molecules.

  • Placental Alkaline Phosphatase, a GPI-anchored protein, is clustered in clathrin-coated vesicles.
    Biochemical and biophysical research communications, 1992
    Co-Authors: Ricardo Makiya, Lars-eric Thornell, Torgny Stigbrand
    Abstract:

    Abstract Pure clathrin-coated vesicles were prepared from a fresh human placenta. The analysis of their content revealed the presence of transferrin, low density lipoproteins, IgG and Placental Alkaline Phosphatase. Since the latter is a membrane protein anchored by a glycan-phosphatidyl inositol (GPI) moiety, its presence in coated vesicles was unexpected. Placental Alkaline Phosphatase is neither adsorbed to the surface of the vesicles, nor appearing due to plasma membrane contaminants, but is located in the lumen of the vesicles. The presence of Alkaline Phosphatase in coated vesicles strenghthens its postulated physiological role in the transcytosis of IgG molecules in placenta.

  • Placental Alkaline Phosphatase is related to human IgG internalization in HEp2 cells.
    Biochemical and biophysical research communications, 1992
    Co-Authors: Ricardo Makiya, Torgny Stigbrand
    Abstract:

    Abstract The biological function(s) of Placental Alkaline Phosphatase has not yet been unraveled. The low catalytic activity of the enzyme at physiological pH, and the lack of “natural substrates”, bring about the necessity of a more structure-related conception of its role. We have observed an interaction between Placental Alkaline Phosphatase and human IgG. In this report we show that this isozyme is the major membrane protein able to bind IgG in a IgG-internalizing cell line (HEp2). Pretreatment of these cells with Fab fragments of anti Placental Alkaline Phosphatase antibodies blocks the internalization of IgG without perturbing the endocytosis of other ligands. Our results indicate that Placental Alkaline Phosphatase has the ability not only to bind human IgG, but also to promote its internalization in HEp2 cells.