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CHARACTERIZATION AND REGULATION OF CONSTITUTIVE TRANSPORT INTERMEDIATES INVOLVED IN TRAFFICKING FROM THE TRANS ‐GOLGI NETWORK
Author(s) -
McLauchlan Hilary J.,
James John,
Lucocq John M.,
Ponnambalam Sreenivasan
Publication year - 2001
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1006/cbir.2001.0717
Subject(s) - endosome , microbiology and biotechnology , golgi apparatus , vesicle , endocytosis , transport protein , biology , chemistry , membrane , biochemistry , intracellular , receptor , endoplasmic reticulum
Transport vesicles or containers (TCs) mediate constitutive protein transport between the trans ‐Golgi network (TGN) and the plasma membrane. A key question is the nature and regulation of these transport containers or intermediates. We have used a trans ‐Golgi network resident, TGN38, to investigate TC formation. TGN38 is a recycling membrane glycoprotein that moves to the cell surface via constitutive membrane traffic and returns via the endosomal pathway. An in vitro assay to measure TC formation was devised using rat liver Golgi membranes, cytosolic factors and ATP. Transport intermediates containing TGN38 were produced and found to be smooth vesicles and tubules of up to 200nm in length. These membrane‐enclosed structures contain different constitutively secreted membrane glycoproteins, including molecules involved in immune functions such as MHC Class I and the polymeric Ig receptor, showing that these intermediates correspond to TCs that have been previously identified in vivo . Importantly, TC formation can be stimulated or inhibited by protein kinase and phosphatase inhibitors, showing regulation by intracellular signalling pathways.