GLRX3 and Iron deficiency anemia: These observations as well as the fact that S. pombe Grx4 serves as a regulator for two distinct iron-regulated transcription factors, Php4 and Fep1, under conditions of high and low levels of iron, led us to investigate whether Fra1- and BolA-like proteins were involved in the Grx4-sensing pathway that inactivates Fep1 in response to iron deficiency.