A Possible Role for Ligatin and the Phosphoglycoproteins It Binds in Calcium-Dependent Retinal Cell Adhesion

✍ Scribed by Richard B. Marchase; Lillian A. Koro; Charles M. Kelly; David R. McClay

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: English
• Weight: 664 KB
• Volume: 18
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.1982.240180407

✦ Synopsis

Abstract

Ligatin is a filamentous plasma membrane protein that serves as a baseplate for the attachment of peripheral glycoproteins to the external cell surface. Ligatin can be released from intact, embryonic chick neural retinal cells by treatment with 20 mM Ca^++^ without adversely affecting their viability. α‐Glucose‐1‐phos phate is also effective in removing ligatin‐associated glycoproteins from intact cells. After either of these treatments, the retinal cells seem not to exhibit Ca^++^ ‐dependent adhesion for one another. It is thus suggested that ligatin in neural retina may serve as a baseplate for the attachment to the cell surface of glycoproteins active in Ca^++^‐dependent adhesion. The finding that Ca^++^ serves to protect Ca^++^‐dependent adhesion molecules from digestion by trypsin is discussed in relation to steric constraints on trypsin's accessibility to these adhesion molecules because of their possible binding to arrayed ligatin filaments.