Globin, coordination with heme synthesis

The rabbit reticulocyte, which synthesizes about 90 of its protein as hemoglobin, offers one of the best examples of translational control of protein synthesis in animal cells. In the complete absence of a nucleus (which is extruded from the cell during its maturation) it coordinates the production of the a and R chains of globin, both with each other and with the supply of heme. However, the exact mechanism of this translational control is not yet fully understood, and only a partial description of what appears to be a surprisingly complex process can be given below. 

Coordination of heme and globin synthesis is the rule during erythropoiesis. While heme is synthesized in mitochondria, protein s)mthesis occurs in the endoplasmic reticulum. Control between compartments may have more far-reaching effects than merely coordinated hemoglobin manufacture. Indeed, there is evidence from studies with deprivation of amino acids, glucose, or oxygen that protein synthesis is coupled in some manner to the metabolic economy. So conceived, the role of hemin in the cytochromes may serve as the nexus between the... 

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