HSP90 exerts its function through the remodelling of different proteins and thus contributes to various biological activities under non-stress conditions. Our combined data showing association of cell surface HSP90 with migration processes in the developing nervous system attribute a novel  biological role to this molecule. Moreover our findings prompt us to  hypothesize that cell surface HSP90 may be necessary to maintain proper conformation of  membrane receptor (s) contributing thus to the ligand-receptor interaction which in turn will activate the cytoplasmic signal transduction cascades  leading to cytoskeletal rearrangement essential for cell motility. However interaction of HSP90 with extracellular signal molecules which will lead to the proper orientation of these molecules for binding to membrane receptors associated with cytoskeletal dynamics cannot be excluded. The  aim of our work is the elucidation of  the molecular interactions of cell surface HSP90 during cell migration events