Your browser doesn't support javascript.
loading
Probing platelet factor 4 alpha-granule targeting.
Briquet-Laugier, V; Lavenu-Bombled, C; Schmitt, A; Leboeuf, M; Uzan, G; Dubart-Kupperschmitt, A; Rosa, J-P.
Afiliação
  • Briquet-Laugier V; U348 INSERM, IFR6-Circulation, Hôpital Lariboisière, Paris, France.
J Thromb Haemost ; 2(12): 2231-40, 2004 Dec.
Article em En | MEDLINE | ID: mdl-15613031
The storage mechanism of endogenous secretory proteins in megakaryocyte alpha-granules is poorly understood. We have elected to study the granule storage of platelet factor 4 (PF4), a well-known platelet alpha-granule protein. The reporter protein green fluorescent protein (GFP), PF4, or PF4 fused to GFP (PF4-GFP), were transfected in the well-characterized mouse pituitary AtT20 cell line, and in the megakaryocytic leukemic DAMI cell line. These proteins were also transduced using a lentiviral vector, in human CD34+ cells differentiated into megakaryocytes in vitro. Intracellular localization of expressed proteins, and colocalization studies were achieved by laser scanning confocal microscopy and immuno-electronmicroscopy. In preliminary experiments, GFP, a non-secretory protein (no signal peptide), localized in the cytoplasm, while PF4-GFP colocalized with adrenocorticotropin hormone (ACTH)-containing granules in AtT20 cells. In the megakaryocytic DAMI cell line and in human megakaryocytes differentiated in vitro, PF4-GFP localized in alpha-granules along with the alpha granular protein von Willebrand factor (VWF). The signal peptide of PF4 was not sufficient to specify alpha-granule storage of PF4, since when PF4 signal peptide was fused to GFP (SP4-GFP), GFP was not stored into granules in spite of its efficient translocation to the ER-Golgi constitutive secretory pathway. We conclude that the PF4 storage pathway in alpha-granules is not a default pathway, but rather a regular granule storage pathway probably requiring specific sorting mechanisms. In addition PF4-GFP appears as an appropriate probe with which to analyze alpha-granule biogenesis and its alterations in the congenital defect gray platelet syndrome.
Assuntos
Buscar no Google
Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Fator Plaquetário 4 / Grânulos Citoplasmáticos Limite: Animals Idioma: En Revista: J Thromb Haemost Assunto da revista: HEMATOLOGIA Ano de publicação: 2004 Tipo de documento: Article País de afiliação: França
Buscar no Google
Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Fator Plaquetário 4 / Grânulos Citoplasmáticos Limite: Animals Idioma: En Revista: J Thromb Haemost Assunto da revista: HEMATOLOGIA Ano de publicação: 2004 Tipo de documento: Article País de afiliação: França