Abstract
Purpose::
Myocilin is known to be secreted into an aqueous humor. In this study, secreted myocilin was applied to various cultured cells to investigate whether specific interaction with cell surface protein may occur.
Methods::
Histidine-tagged recombinant myocilin was expressed in COS-1 cells and the culture medium containing the secreted myocilin was collected. This medium was added RGC-5, A549, and NIH3T3 cells and these cells were cultured for 72-96 hours. Cell surface distribution of myocilin was determined by immunostaining.
Results::
Immunofluorescence microscopic analysis revealed that secreted myocilin was bound specifically to cell surface of NIT3T3 cells. Localization of myocilin was dot-like pattern, and this interaction was dependent on cell density. Binding of myocilin to cell surface was not observed at the low density of 7.5 x 102/cm2, whereas myocilin could associate with NIH3T3 cells at the high density of 1.5 x 103/cm2. Recombinant myocilin and unknown cell surface protein(s) were cross-linked by membrane impermeable cross-linker (sulfosuccinimidylpropionate) followed by cell lysis and immunoprecipitation.
Conclusions::
Myocilin was shown to interact with cell surface in a specific manner. These results indicate that myocilin is capable of cell surface interaction. Currently, precipitated proteins are under investigation.
Keywords: cell-cell communication • trabecular meshwork • signal transduction