@article{180401,
  keywords = {Animals, signal transduction, Recombinant Proteins, Biological Transport, Molecular Sequence Data, Cell Line, Amino Acid Sequence, Mice, Fibronectins, Cell Aggregation, Organelles, Adrenocorticotropic Hormone, Pituitary Gland, beta-Endorphin},
  author = {Castle and Schwarzbauer and Wright and Castle},
  title = {Differential targeting of recombinant fibronectins in AtT-20 cells based on their efficiency of aggregation},
  abstract = {<p>In pituitary-derived AtT-20 cells, recombinant fibronectin containing the N-terminal matrix assembly domain and the C-terminal half of fibronectin does not follow the regulated secretory pathway but instead concentrates in distinct organelles prior to secretion. These organelles are larger than the dense-core granules and localize to the cell body at sites that differ from lysosomes, endosomes and endoplasmic reticulum. Unlike the dense-core granules, their discharge is not stimulated by 8-bromo-cyclic-AMP or phorbol esters. The kinetics of intracellular transport and secretion of the recombinant fibronectin suggest that it is present in a post-Golgi pool that turns over more slowly than constitutive vesicles. Indeed, the fibronectin-containing organelles disappear with a half-time of 3 hours after inhibiting protein synthesis. Presence of the organelles correlates with intracellular aggregation of dimeric fibronectin polypeptides. The organelles are absent in cells expressing monomeric recombinant fibronectin (lacking C-terminal dimerization sites) or the C-terminal half of fibronectin (which dimerizes but lacks the N-terminal matrix assembly domain), both of which aggregate less efficiently than dimeric fibronectin. Instead, the latter polypeptides enter the dense-core granules. Thus while the formation of the fibronectin-containing organelles may require efficient aggregation, it may not require a specific structural signal. Moreover, efficient aggregation is not necessarily a prerequisite for following the regulated pathway.</p>
},
  year = {1995},
  journal = {J Cell Sci},
  volume = {108 ( Pt 12)},
  pages = {3827-37},
  month = {12/1995},
  issn = {0021-9533},
  language = {eng},
}