Apical Polarization of N-CAM in Retinal Pigment Epithelium Is Dependent on Contact with the Neural Retina

• Published in: The Journal of cell biology 1993-04, Vol.121 (2), p.335-343
• Main Authors: Gundersen, Doris, Powell, Sharon K., Rodriguez-Boulan, Enrique
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Cadherins; Cell Adhesion; Cell Adhesion Molecules, Neuronal - metabolism; Cell Compartmentation; Cell interactions, adhesion; Cell lines; Cell Membrane - metabolism; Cell Polarity; Cells, Cultured - metabolism; Cellular biology; Cultured cells; Epithelial cells; Fundamental and applied biological sciences. Psychology; Molecular and cellular biology; Molecular Weight; Neural cell adhesion molecules; Neurons; Ophthalmology; Photoreceptors; Pigment Epithelium of Eye - metabolism; Pigments; Protein isoforms; Rats; Retina; Retina - metabolism
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.121.2.335

The retinal pigment epithelium (RPE) is unique among epithelia in that its apical surface does not face a lumen, but, instead, is specialized for interaction with the neural retina. The molecules involved in the interaction of the RPE with the neural retina are not known. We show here that the neural cell adhesion molecule (N-CAM) is found both on the apical surface of RPE in situ and on the outer segments of photoreceptors, fulfilling an important requisite for an adhesion role between both structures. Strikingly, culture of RPE results in rapid redistribution of N-CAM to the basolateral surface. This is not due to an isoform shift, since the N-CAM expressed by cultured cells (140 kD) is the same as that expressed by RPE in vivo. Rather, the reversed polarity of N-CAM appears to result from the disruption of the contact between the RPE and the photoreceptors of the neural retina. We suggest that N-CAM in RPE and photoreceptors participate in these interactions.