Par-1 promotes a hepatic mode of apical protein trafficking in MDCK cells.
Simple (i.e., nonstratified) epithelial cells use two different routes to target their newly synthesized luminal plasma membrane proteins to the cell surface: a direct route from the Golgi complex, as in the kidney-derived MDCK cell line, or an indirect route that involves a intermediate stop at the ab-luminal (basolateral) membrane, as in hepatocytes. The mechanisms or proteins responsible for these different protein targeting strategies are not known. Here, we show that increased expression of EMK1, a mammalian ortholog of Caenorhabditis elegans Par-1, in MDCK cells promotes a switch from a direct to a transcytotic mode of apical protein delivery and other trafficking changes typical of hepatocytes. These results, together with our recent demonstration that PAR-1 promotes morphological features of hepatocytes in MDCK cells, indicate that Par-1 modulates the developmental decision to build a columnar versus a hepatic epithelial cell. To our knowledge, Par-1 is the first gene assigned to this task in epithelial morphogenesis.
Cohen
David
D
Dyson Vision Research Institute, Weill Medical College of Cornell University, New York, NY 10021, USA.
Rodriguez-Boulan
Enrique
E
Müsch
Anne
A
D000818:Animals; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D016764:Cell Polarity; D004285:Dogs; D004847:Epithelial Cells / Q000166:cytology; D006056:Golgi Apparatus / Q000378:metabolism; D007668:Kidney; D008099:Liver / Q000166:cytology*; D009024:Morphogenesis; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism*; D021381:Protein Transport
D029742:Caenorhabditis elegans Proteins; C489440:EMK1 protein, Canis familiaris; C409406:PAR-1 protein, C elegans; D017346:Protein Serine-Threonine Kinases