Formation of Assemblies on Cell Membranes by Secreted Proteins: Molecular Studies of Free Lambda Light Chain Aggregates Found on the Surface of Myeloma Cells

In this study, we describe the presence of λFLCs on the surface of myeloma cells. We found that cell surface-associated λFLC are bound directly to the membrane and in an aggregated form. Subsequently, membrane interaction studies revealed that λFLCs interact with saturated zwitterionic lipids such as phosphatidylcholine and phosphatidylethanolamine, and using automated docking, we characterize a potential recognition site for these lipids. Atomic force microscopy confirmed that membrane-associated
λFLCs are aggregated. Given our findings, we propose a model whereby individual FLCs show modest affinity for zwitterionic lipids, with aggregation stabilizing the interaction due to multivalency. Notably, this is the first study to image FLCs bound to phospholipids and provides important insights into the possible mechanisms of membrane association by this unique myeloma surface antigen.

Source: BJ Cell - July 4, 2013 Category: Biochemistry Authors: A T Hutchinson, A Malik, M B Berkahn, M Agostino, J To, J L Tacchi, S P Djordjevic, L Turnbull, C B Whitchurch, A B Edmundson, D R Jones, R L Raison, P A Ramsland Tags: BJ Cell Source Type: research