Previous research from our laboratory has revealed dramatic differences in the targeting of several apical and basolateral plasma membrane proteins between Retinal Pigment Epithelium (RPE) and other simple epithelia. The model apical protein, Influenza Hemagglutinin (HA), follows a transcytotic route in RPE rather than the conventional direct route between Trans Golgi Network (TGN) and apical cell surface observed in other epithelial cells. Basolateral proteins such as NCAM-140 and RET-PE2 (EMMPRIN) have a strikingly reversed apical polarity in adult RPE but the latter is basolateral in the immature RPE of newborn rats. This proposal addresses the fundamental mechanisms involved in the establishment of polarity in RPE. Experiments in aim l will characterize the role of components of the apical sorting machinery, such as caveolin, MAL proteolipid, lectin and non-lectin receptors in the targeting of HA and other apical proteins in RPE (aim 1). Experiments in aim 2 will explore the mechanisms responsible for the apical reversal of NCAM and EMMPRIN. To accomplish this, we will analyze the role of known adaptor complexes (AP1, AP3, AP4), of ubiquilin (a protein that associates with the basolateral signal of NCAM) and of recently identified TGN-associated adaptors, in the basolateral sorting of these molecules. We will identify the basolateral signal of EMMPRIN and, as this protein is ubiquitinated, determine the role of ubiquitination in basolateral targeting. Experiments in aim 3 will continue to characterize the role of ezrin in RPE morphogenesis. We have recently shown that ezrin is key to the development of the very long apical microvilli and the highly convoluted basal infoldings during maturation of RPE in newborn rats. We will search for binding partners of ezrin at apical and basolateral surfaces and assess their specific roles in these processes. We will determine how ezrin is activated by phosphorylation and determine the role of kinases and small GTPases that participate in this process. We will study how blocking ezrin synthesis in vivo affects the maturation of RPE microvilli and associated photoreceptors. The information obtained should help understand the role of RPE in a variety of blinding diseases, such as age-related macular degeneration and diabetic retinopathy.
| Tanos, Barbara E; Yeaman, Charles; Rodriguez-Boulan, Enrique (2018) An emerging role for IQGAP1 in tight junction control. Small GTPases 9:375-383 |
| Benedicto, Ignacio; Lehmann, Guillermo L; Ginsberg, Michael et al. (2017) Concerted regulation of retinal pigment epithelium basement membrane and barrier function by angiocrine factors. Nat Commun 8:15374 |
| Caceres, Paulo S; Benedicto, Ignacio; Lehmann, Guillermo L et al. (2017) Directional Fluid Transport across Organ-Blood Barriers: Physiology and Cell Biology. Cold Spring Harb Perspect Biol 9: |
| Perez Bay, Andres E; Schreiner, Ryan; Benedicto, Ignacio et al. (2016) The fast-recycling receptor Megalin defines the apical recycling pathway of epithelial cells. Nat Commun 7:11550 |
| 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 |
| Song, Minseok; Giza, Joanna; Proenca, Catia C et al. (2015) Slitrk5 Mediates BDNF-Dependent TrkB Receptor Trafficking and Signaling. Dev Cell 33:690-702 |
| 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 |
| Nociari, Marcelo M; Lehmann, Guillermo L; Perez Bay, Andres E et al. (2014) Beta cyclodextrins bind, stabilize, and remove lipofuscin bisretinoids from retinal pigment epithelium. Proc Natl Acad Sci U S A 111:E1402-8 |
| Rodriguez-Boulan, Enrique; Macara, Ian G (2014) Organization and execution of the epithelial polarity programme. Nat Rev Mol Cell Biol 15:225-42 |
Showing the most recent 10 out of 56 publications
