Collagen prolyl 4-hydroxylase (C-P4H) alpha subunit is of regulatory importance in the assembling of C-P4H tetramers, which are necessary for the hydroxylation of pro-collagen chains. Change in collagen expression by hypoxia or iron-diminishment is a significant issue in extracellular matrix remodeling. Here we report that the induction of C-P4H-alpha(I) in human fibrosarcoma cells HT1080 by the iron chelator 2,2-Dipyridyl is predominantly caused by an enhancement of mRNA stability. This effect is mediated by an increased synthesis and binding of hnRNP-A2/B1, which interact with a (U)16-element located in the 3'-untranslated region of C-P4H-alpha(I) mRNA. Luciferase reporter gene assays depending on C-P4H-alpha(I) 3'UTR and co-transfection with hnRNP-A2/B1 provide evidence that the (U)16-element is necessary and sufficient for posttranscriptional control of C-P4H-alpha (I) synthesis under the analyzed conditions. Further indication for the significance of hnRNP-A2/B1 in C-P4H-alpha(I) induction was obtained by micro array experiments. In a dataset of 686 independent physiological conditions we found a significant positive correlation between hnRNP-A2/B1 and C-P4H-alpha (I) mRNAs. Thus, hnRNP-A2/B1 are demonstrated as factors participating in collagen metabolism.