ERN1 and neutropenia: In the neutropenia phase, the protein HSPA5 interacts with proteins localized in the cell cytoskeleton (PRKC apoptosis WT1 regulator protein), membrane (spartin), extracellular matrix (dermokine and thyroglobulin), and in the endoplasmic reticulum (SIL1, DnaJC10, DnaJB11, Sec61A1, EIF2AK3, and ERN1).