The emerging roles of somatic globins in cardiovascular redox biology and beyond

Abstract

The vertebrate globins are a group of hemoproteins with the intrinsic capacity to regulate gaseous ligands and redox signaling required for cardiovascular biology. This graphical review will provide a comprehensive synopsis of somatic cardiovascular globins focusing on expression, function and redox signaling - an emerging area in both physiology and disease.

Keywords: Cariovascular; Cytochrome b5 reductase; Cytoglobin; Globin; Hemoglobin; Myoglobin; Neuroglobi; Nitric oxide.

Fig. 1

Schematic outline of the vertebrate globins in the cardiovascular system highlighting cell-type specific expression, biochemical functions and phylogenetic features.

Fig. 2

Cell type-specific expression of hemoglobin, myoglobin, cytoglobin and neuroglobin along the vascular tree.

Fig. 3

Mechanism of Hb α-regulated NO signaling in endothelial cells. Hb α is expressed in small artery and arteriolar endothelial cells and enriched at the myoendothelial junction (lower left hand corner). Nitric oxide, released from eNOS, reacts with oxy-Hb ${\mathrm{\alpha }}^{{\mathrm{Fe}}^{2+}}$ resulting in NO scavenging (dioxygenation reaction) or reacts with Hb ${\mathrm{\alpha }}^{{\mathrm{Fe}}^{3+}}$ resulting in a slow and weak binding NO allowing for diffusion. The cycling of Hb ${\mathrm{\alpha }}^{{\mathrm{Fe}}^{3+}}$ to Hb ${\mathrm{\alpha }}^{{\mathrm{Fe}}^{2+}}$ is controlled by a CytB5 and CytB5R3 dependent mechanism.

Fig. 4

Known somatic cell types that express hemoglobin, the identified chains, and functions.