The understanding of the sorting out mechanisms involved in the specific delivery of proteins from the site of synthesis to the site of function constitutes a central question in Cell Biology. One aspect of this is the asymmetric distribution of plasma membrane proteins between apical and basolateral surfaces in epithelial cells. To study the mechanisms responsible for this polarity, we have developed a model system consisting of kidney epithelial cells (MDCK) infected with enveloped viruses. Using this model system we plan: (a) to localize the intracellular site of sorting of apical and basolateral glycoproteins and to identify """"""""carrier vesicles"""""""" that transport them to the respective plasma membrane domain by immunoelectron microscopy on monolayers double infected with temperature sensitive mutants of apically (influenza) and basolaterally (vesicular stomatitis virus -VSV) budding viruses. We will attempt to identify apical receptors involved in the polarized exocytosis of influenza hemagglutinin (HA) to the apical surface using monoclonal antibodies raised against the surface of MDCK cells; (b) to characterize structurally and functionally the apical and basolateral endosomal populations of MDCK cells and to investigate whether the exocytic route of HA involves the endosomal compartment; (c) to search for pharmacologic (anticytoskeletal agents; calmodulin inhibitors, etc.) and physiologic (transmonolayer electric gradient) conditions that may specifically affect the apical and basolateral exocytic pathways; (d) to isolate cellular mutants in the apical pathway; (e) to develop an """"""""in vitro"""""""" assay for the delivery of viral glycoproteins to the cell surface; (f) to study the polarity properties of """"""""inverted epithelia"""""""" (choroid plexus, eye pigmentary epithelium); (g) to investigate the relationship between development of functional tight junctions and development of polarity. These studies should help to elucidate the biological basis of polarized epithelial cell function, central to the function of kidney, liver, intestine, and exocrine glands. Furthermore, since epithelia are usually the first barriers to viruses, they may also provide insights on how viral disease spreads in the organism.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM034107-06
Application #
3284612
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1984-02-01
Project End
1991-01-31
Budget Start
1989-02-01
Budget End
1990-01-31
Support Year
6
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Weill Medical College of Cornell University
Department
Type
Schools of Medicine
DUNS #
201373169
City
New York
State
NY
Country
United States
Zip Code
10065
Tanos, Barbara E; Yeaman, Charles; Rodriguez-Boulan, Enrique (2018) An emerging role for IQGAP1 in tight junction control. Small GTPases 9:375-383
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Tanos, Barbara E; Perez Bay, Andres E; Salvarezza, Susana et al. (2015) IQGAP1 controls tight junction formation through differential regulation of claudin recruitment. J Cell Sci 128:853-62
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Bay, Andres E Perez; Schreiner, Ryan; Rodriguez-Boulan, Enrique (2015) Structural and functional analysis of endosomal compartments in epithelial cells. Methods Cell Biol 130:271-88
Thuenauer, Roland; Hsu, Ya-Chu; Carvajal-Gonzalez, Jose Maria et al. (2014) Four-dimensional live imaging of apical biosynthetic trafficking reveals a post-Golgi sorting role of apical endosomal intermediates. Proc Natl Acad Sci U S A 111:4127-32
Rodriguez-Boulan, Enrique; Macara, Ian G (2014) Organization and execution of the epithelial polarity programme. Nat Rev Mol Cell Biol 15:225-42

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