Rabbit Anti-Human HSPA1A polyclonal antibody for IHC-P, WB. The HSP70 family is composed of four highly conserved proteins: HSP70, HSC70, GRP75 and GRP78. These proteins serve a variety of roles: they act as molecular chaperones facilitating the assembly of multi-protein complexes, they participate in the translocation of polypeptides across cell membranes and to the nucleus and they aid in the proper folding of nascent polypeptide chain. HSP70 expression is strongly induced in response to heat stress.