Discovery of cytoglobin and its roles in physiology and pathology of hepatic stellate cells

Cytoglobin (cygb),a new member of the globin family,was discovered in 2001 as a protein associated with stellate cell activation (stellate cell activation-associated protein [stap]). knowledge of cygb,including its crystal,gene,and protein structures as well as its physiological and pathological importance,has increased progressively. we investigated the roles of oxygen (o2)-binding cygb as stap in hepatic stellate cells (hscs) to understand the part played by this protein in their pathophysiological activities. studies involving cygb-gene-deleted mice have led us to suppose that cygb functions as a regulator of o2 homeostasis; when o2 homeostasis is disrupted,hscs are activated and play a key role(s) in hepatic fibrogenesis. in this review,we discuss the rationale for this hypothesis. © 2016 the japan academy.