Iron homeostasis in cells is regulated by iron regulatory proteins (IRPs) that exist in different organisms. IRPs are cytosolic proteins that bind to iron-responsive elements (IREs) of the 5'- or 3'-untranslated regions (UTR) of mRNAs that encode many proteins involved in iron metabolism. In this study, we have cloned and described a new regulatory protein belonging to the family of IRPs from the earthworm Eisenia andrei (EaIRP). The earthworm IRE site in 5'-UTR of ferritin mRNA most likely folds into a secondary structure that differs from the conventional IRE structures of ferritin due to the absence of a typically unpaired cytosine that participates in protein binding. Prepared recombinant EaIRP and proteins from mammalian liver extracts are able to bind both mammalian and Eisenia IRE structures of ferritin mRNA, although the affinity of the rEaIRP/Eisenia IRE structure is rather low. This result suggests the possible contribution of a conventional IRE structure. When IRP is supplemented with a Fe-S cluster, it can function as a cytosolic aconitase. Cellular cytosolic and mitochondrial fractions, as well as recombinant EaIRP, exhibit aconitase activity that can be abolished by the action of oxygen radicals. The highest expression of EaIRP was detected in parts of the digestive tract. We can assume that earthworms may possess an IRE/IRP regulatory network as a potential mechanism for maintaining cellular iron homeostasis, although the aconitase function of EaIRP is most likely more relevant.

• MeSH
• akonitáthydratasa metabolismus   MeSH
• ferritin metabolismus   MeSH
• fylogeneze MeSH
• homeostáza fyziologie   MeSH
• konformace nukleové kyseliny MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• messenger RNA genetika   MeSH
• molekulární sekvence - údaje MeSH
• Oligochaeta růst a vývoj   metabolismus   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• proteiny regulující obsah železa genetika   metabolismus   MeSH
• regulační oblasti nukleových kyselin genetika   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• vazba proteinů MeSH
• železo metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Human untranslated region (UTR) databases were searched to identify novel proteins potentially regulated by an iron responsive element (IRE), and found two candidates-cell cycle phosphatase Cdc14A variant 1 and myotonic dystrophy kinase-related Cdc42-binding kinase alpha (MRCKalpha), both possessing a putative IRE in their 3'UTR. In further experiments, we focused on MRCKalpha. Biochemical analyses of the MRCKalpha IRE revealed that it was functional and mediated the response to iron level in the same way as transferrin receptor 1 IREs (TfR) did. Similarly to TfR mRNA, MRCKalpha mRNA is stabilized, when iron supply is low, while it is destabilized under iron-rich conditions. The expression of MRCKalpha mRNA was found to be ubiquitous; the highest levels were noted in testes, the lowest in skeletal muscle. The level of MRCKalpha mRNA in various tissues strongly positively correlates with the level of TfR mRNA, indicating its possible role in the transferrin iron uptake pathway.

• MeSH
• buňky K562 MeSH
• CD antigeny metabolismus   MeSH
• financování organizované MeSH
• lidé MeSH
• nepřekládané oblasti genetika   MeSH
• protein-serin-threoninkinasy genetika   metabolismus   MeSH
• proteiny regulující obsah železa genetika   metabolismus   MeSH
• receptory transferinu metabolismus   MeSH
• železo farmakologie   MeSH
• Check Tag
• lidé MeSH