Determination of metal interactions with the chaperone Hspa5 in human astrocytoma cells and rat astrocyte primary cultures.

Molecular chaperones assist the folding of nascent proteins during translation into their correct conformations. Neurotoxic metals such as copper (Cu) and lead (Pb) may produce a deficiency in chaperone function that compromises protein secretion and exacerbates protein aggregation, potentially promoting neurodegenerative diseases that exhibit protein aggregation. Because astrocytes function as depots in the brain for certain metals, including Cu and Pb, the interaction of metals with chaperones in these cells is of interest. Furthermore, Pb and Cu bind strongly to the molecular chaperone heat shock 70 kDa protein Hspa5, also known as glucose-regulated protein 78 (Grp78) or immunoglobulin-binding protein (BiP). This chapter describes methods for expressing fluorescent chimeric proteins in astrocytes and astrocytoma cells in order to examine the metal-induced cytosolic redistribution of Hspa5, as well as associated effects on the secretion of interleukin-6 (IL-6).