Probably plays a role in facilitating the assembly of multimeric protein complexes inside the ER. ATP + H2O = ADP + H(+) + phosphate Expressed in pollen and nuts (at protein level). Expressed during pollen development. At the immature, bicellular stage, expressed exclusively in the intine. At the mature, tricellular stage, expressed at the boundary of cytoplasm and intine of the pollen grains, specifically in the region of the germinal apertures. The strongest expression at the mature stage is shown under normal environmental conditions. After germination, expressed at the tip region of the pollen tube. The N-terminus is blocked. Causes an allergic reaction in human. Binds to IgE in 71% of the 7 patients tested allergic to tree pollen, including hazel and birch pollen. Belongs to the heat shock protein 70 family.