Nursing hemoglobin

Molecular chaperones help maintain the structural integrity of other proteins and as such have been proposed to control hemoglobin stability — although this has so far remained unproven. In 13 June Nature, Anthony Kihm and colleagues at University of Pennsylvania, USA, describe a newly identified erythroid protein that function as a chaperone, stabilizing free α-hemoglobin and preventing precipitation (Nature 2002, 417:758-763).

Kihm et al. performed a screen to search for genes induced by the essential erythroid transcription factor GATA-1 and identified an abundant, erythroid-specific protein that forms a stable complex with free α-hemoglobin but not with β-hemoglobin or hemoglobin A (α2β2). They observed that this molecule (named Alpha Hemoglobin Stabilizing Protein – AHSP) specifically protects free α-hemoglobin from precipitation in solution and in live cells. In addition, the AHSP-gene-ablated mice exhibited reticulocytosis and abnormal erythrocyte morphology with intracellular inclusion bodies that stain positively for denatured hemoglobin.

"If a mutated or ...