HSPA4 and viral infectious disease: Complementarily, HSPs (in particular HSP70 and HSP40) are known to be directly involved in virus replication (Hofius et al., 2007; Hafrén et al., 2010; Nagy and Pogany, 2010; Jungkunz et al., 2011; Mäkinen and Hafrén, 2014), and virus infections at early stages may modulate (facilitate or inhibit) synthesis of HSPs (Whitham et al., 2003).