Component of the transcription regulatory CCAAT-binding complex. Required for the reprogramming of the cell for iron use. Down-regulates pcl1, sdh4, and isa1 underlow-iron conditions. Component of tha CCAAT-binding complex composed of at least php2, php3, php4 and php5 (By similarity). Interacts with crm1 and grx4. Iron starvation induces nuclear accumulation and iron induces relocalization to the cytoplasm, in association with exportin crm1. Expressed is under the control of the iton-regulatory transcription factor fep1. Expression is repressed under iron-replete conditions and induced under conditions of iron starvation.