Although not directly shown in C. elegans, BiP/GRP78 (HSP-3 or HSP-4 in C. elegans) has been shown to bind to PEK-1 in its monomeric state in other organisms. Unfolded proteins are thought to compete with PEK-1 for binding to BiP/GRP78 such that an increased load of unfolded proteins would cause dissociation of BiP/GRP78 from PEK-1, thereby allowing PEK-1 dimerization and subsequent eIF2-alpha phosphorylation, and thus inhibition of translation.