Of Two Cytosolic Aconitases Expressed in Drosophila, Only One Functions as an Iron-regulatory Protein

In mammalian cells, iron homeostasis is largely regulated by post-transcriptional control of gene expression through the binding of iron-regulatory proteins (IRP1 and IRP2) to iron-responsive elements (IREs) contained in the untranslated regions of target mRNAs. IRP2 is the dominant iron sensor in mammalian cells under normoxia, but IRP1 is the more ancient protein in evolutionary terms and has an additional function as a cytosolic aconitase. The Caenorhabditis elegans genome does not contain an IRP2 homolog or identifiable IREs; its IRP1 homolog has aconitase activity but does not bind to mammalian IREs. The Drosophila genome offers an evolutionary intermediate containing two IRP1-like proteins (IRP-1A and IRP-1B) and target genes with IREs. Here, we used purified recombinant IRP-1A and IRP-1B from Drosophila melanogaster and showed IRP-1A bind to proteins aconitase in from IRP-1A and IRP-1B in and of but not of in the of the the two showed the IRP1 binding as a the of the the ancient cytosolic aconitase in with In mammalian cells, iron homeostasis is largely regulated by post-transcriptional control of gene expression through the binding of iron-regulatory proteins (IRP1 and IRP2) to iron-responsive elements (IREs) contained in the untranslated regions of target mRNAs. IRP2 is the dominant iron sensor in mammalian cells under normoxia, but IRP1 is the more ancient protein in evolutionary terms and has an additional function as a cytosolic aconitase. The Caenorhabditis elegans genome does not contain an IRP2 homolog or identifiable IREs; its IRP1 homolog has aconitase activity but does not bind to mammalian IREs. The Drosophila genome offers an evolutionary intermediate containing two IRP1-like proteins (IRP-1A and IRP-1B) and target genes with IREs. Here, we used purified recombinant IRP-1A and IRP-1B from Drosophila melanogaster and showed IRP-1A bind to proteins aconitase in from IRP-1A and IRP-1B in and of but not of in the of the the two showed the IRP1 binding as a the of the the ancient cytosolic aconitase in with is and is and regulated by and In control of iron of the of iron is the In of iron is by IRP1 and bind to iron-responsive elements (IREs) used iron-responsive iron-regulatory expression used iron-responsive iron-regulatory expression in the regions of or iron IRP1 and IRP2 bind to in the regions of proteins function in iron the and iron is in IRP1 and IRP2 iron IRP1 an protein with aconitase activity and the to the IRP2 has an additional in the protein and has aconitase activity of has to the IRP2 mammalian iron IRP1 to the of iron to a its is and the protein as an aconitase is and to protein to the is an is in and has binding to a aconitase a of aconitase in the activity in and is the more and of a aconitase gene and cytosolic by genes in Caenorhabditis elegans from or binding activity and in In the and contain cytosolic bind to or mammalian and an intermediate in the of the melanogaster the to binding activity of in an with an of the homolog the two genes in the Drosophila genome to an of the of a protein binding to and a protein cytosolic aconitase activity Drosophila two IRP1-like proteins (IRP-1A and IRP-1B) by genes we purified and proteins and IRP-1A IREs. protein in a and of IRP-1A of and recombinant protein in the to IRP-1A and IRP-1B and the expression and of in Drosophila melanogaster and expression and a in the of the IRP-1A and used to with regions to of the of of by the to the of and used and the and and and and and The of by of the proteins containing from and and of the IRP1 in Drosophila IRP-1A and of of of of in a and and by the Drosophila and The by and with to and IRP-1A in with the The in containing of and of to a of and with to expression of the The cells by of under to the The recombinant protein with containing and The protein by and the protein by the The protein used or The of and to as with the with the or of the in containing of as The recombinant with of the purified IRP-1A and with and the of with the the protein The to or to a The by the and from the and of in Drosophila melanogaster and is from is to a in the binding of activity by the aconitase to and The in a of in the of of recombinant Drosophila IRP-1A or IRP-1B and an of the of to the of is used as the in used as a the aconitase is in and of IRP-1A and and IRP-1B to recombinant with in proteins with a of from by and and by a to The of of recombinant IRP-1A and IRP-1B The of IRP-1A and of protein the by protein of IRP-1A and containing the expression IRP-1A and by The by and in The and from the and to to the recombinant proteins in the the recombinant proteins with containing The of proteins the The and by IRP-1A and IRP-1B of IRP-1A and IRP-1B has to in the of the aconitase proteins as and IRP-1A and IRP-1B aconitase activity as purified The to a of recombinant with an and aconitase activity in the as purified recombinant IRP1 in a melanogaster is the to contain two cytosolic of recombinant IRP-1A and of recombinant IRP-1A and IRP-1B aconitase activity in The activity is as the in and of recombinant in is from with expression used to binding activity of IRP-1A and and IRP-1B and to and and Drosophila and IREs. of recombinant protein in of by in or to IRP-1A to the we bind to an recombinant IRP-1A to bind in Drosophila and in the of a and In IRP-1B not Drosophila or binding activity of IRP-1B the protein in or by and and and not binding and aconitase activity of recombinant IRP-1A and IRP-1B in to iron of recombinant or with and as of the with Drosophila and binding activity by The of the aconitase activity in a The activity is as the in and of recombinant binding activity the binding of IRP-1A to of and to The showed to the the of not the an binding activity IRP-1A with the binding activity of Drosophila to of IRP-1A binding to of Drosophila with of purified in the binding a of or with a in the with the of the of with of as purified from has aconitase activity and to with in and or in by a to with in the of iron has the purified The of iron with to is by of in of aconitase activity and in binding in with mammalian IRP1 In binding activity in with purified but aconitase activity of IRP-1B the of iron and the of to the regions of IRP-1A contain the binding of IRP-1B with from IRP-1A and to with in and purified as and of the purified recombinant proteins to and binding activity with the activity of to The and to bind and Drosophila with an activity of and The and not binding activity of purified protein the not of IRP-1A and IRP-1B in the we in we in and expression of the by of the of IRP-1A in a in a of binding activity of IRP-1B the aconitase activity of by in the of IRP-1A and by IRP-1B of proteins in with binding and aconitase of aconitase by the in activity to from the cytosolic the two proteins by IRP1 binding and aconitase activity of from of protein from of the with and by aconitase of the with of IRP-1B or in with in aconitase activity of the by aconitase the in aconitase activity is to a of cytosolic aconitase of the with IRP1 and IRP-1A and to IRP-1A and IRP-1B with a of the of expression and the of IRP-1A in In IRP-1B and the the two proteins we the of IRP-1A by expression of IRP-1A to a expression of IRP-1A in and not expression in to with or to the with of IRP-1A or IRP-1B in a in a the of two to the of cytosolic or by in the melanogaster and the two proteins IRP-1A is to the mammalian as a cytosolic aconitase or an through the and of a IRP-1B is more to the cytosolic aconitase of is more ancient and IREs. in of IRP-1A and IRP-1B in the binding of IRP-1A in Drosophila and IRP-1A a evolutionary from a of to of IRP1 binding by the of the to of the and is by the The the and the IRP1 binding and in of the IRP1 is with of of IRP-1B with the IRP-1A binding activity to the of the IRP-1A protein of the of the genome of Drosophila and IRP-1A and IRP-1B in the two proteins the as in the two and in the two the two to of the two and the two we in of the protein of or in with regions in binding IRP1 in IRP-1A from two Drosophila in IRP-1B The IRP1 is in binding of in not in not in not in not in not melanogaster and not in not melanogaster and not in not in not in not in IRP-1B and not in not in IRP-1A and not in IRP-1B and not in not melanogaster and IRP-1B and not in not melanogaster and not in not in not in not in not in IRP-1A and IRP-1A and not in not in not melanogaster and not in not in not in not in not melanogaster and IRP-1B and IRP-1A and in a the IRP1 the IRP-1A and IRP-1B of not the binding the and in IRP-1B of in the In a in in a by a of and IRP-1B and in the The of is not the Drosophila the IRP1 in melanogaster IRP-1A and Drosophila IRP-1A but from IRP-1B proteins The is in to the of the the the IRP-1A and IRP-1B of IRP-1A and IRP-1B the IRP1 The and in aconitase activity and binding proteins by and IRP-1B and under The is to in of used the and IRP-1B and with IRP1 the protein of IRP-1A and IRP-1B the of IRP1 the of the with IRP1 the in aconitase activity in binding with the in the IRP1 we Drosophila an to IRP-1A and IRP-1B the of the protein IRP-1A and IRP-1B contain an of a in in IRP-1B) as with the binding is to a an of from in IRP-1B the of in in IRP-1A is a of IRP-1B is in in to the In IRP-1A with the IRP1 in more IRP-1A and IRP1 to The two by to IRP-1A and IRP-1B and in IRP-1B) from the is to the of in IRP-1A an protein in to its of the protein in function in iron and in more the of proteins to the is contained in the and the by of genes and of proteins of function to the through of and of the by a of gene cytosolic aconitase to from and a of cytosolic aconitase two cytosolic in of the two cytosolic to in binding of the of is to as by the The is in the in the and regions not by the to a of a protein with a of an in an and a and a to the the of an gene is or the of to and the of to aconitase function in the is more ancient a of the protein in iron cells to in the and in the and in IRP1 control of the aconitase is in mammalian cells and the of is contained in an a of of we the in by gene of two cytosolic of the to bind to the the and the the to the of the of in or the of or in the as the evolutionary the has a in is the control of is an and the of a cytosolic to control the of iron in the In is the in is in a as to a with is the iron in cells and a target iron evolutionary an of in of the cytosolic as IRP2) and of its activity as an aconitase by of a is the in evolutionary terms is to IRP2 of control of IRP2 by and iron the dominant in mammalian iron is and is and regulated by and In control of iron of the of iron is the In of iron is by IRP1 and bind to iron-responsive elements (IREs) used iron-responsive iron-regulatory expression used iron-responsive iron-regulatory expression in the regions of or iron IRP1 and IRP2 bind to in the regions of proteins function in iron the and iron is in IRP1 and IRP2 iron IRP1 an protein with aconitase activity and the to the IRP2 has an additional in the protein and has aconitase activity of has to the IRP2 mammalian iron IRP1 to the of iron to a its is and the protein as an aconitase is and to The protein to the is an is in and has binding to a aconitase a of aconitase in the activity in and is the more and of a aconitase gene and cytosolic by genes in Caenorhabditis elegans from or binding activity and in In the and contain cytosolic bind to or mammalian and an intermediate in the of the Drosophila melanogaster the to binding activity of in an with an of the homolog the two genes in the Drosophila genome to an of the of a protein binding to and a protein cytosolic aconitase activity Drosophila two IRP1-like proteins (IRP-1A and IRP-1B) by genes we purified and proteins and IRP-1A IREs. protein in a and of IRP-1A of and recombinant protein in the to IRP-1A and IRP-1B and the expression and of in Drosophila melanogaster and expression and a in the of the IRP-1A and used to with regions to of the of of by the to the of and used and the and and and and and The of by of the proteins containing from and and of the IRP1 in Drosophila IRP-1A and of of of of in a and and by the Drosophila and The by and with to and IRP-1A in with the The in containing of and of to a of and with to expression of the The cells by of under to the The recombinant protein with containing and The protein by and the protein by the The protein used or The of and to as with the with the or of the in containing of as The recombinant with of the purified IRP-1A and with and the of with the the protein The to or to a The by the and from the and of in Drosophila melanogaster and is from is to a in the binding of activity by the aconitase to and The in a of in the of of recombinant Drosophila IRP-1A or IRP-1B and an of the of to the of is used as the in used as a the aconitase is in of and recombinant protein in the to IRP-1A and IRP-1B and the expression and of in Drosophila melanogaster and expression and a in the of the IRP-1A and used to with regions to of the of of by the to the of and used and the and and and and and The of by and and by the Drosophila and The by and with to and IRP-1A in with the The in containing of and of to a of and with to expression of the The cells by of under to the The recombinant protein with containing and The protein by and the protein by the The protein used or The of and to as with the with the or of the in containing of as The recombinant with of the purified IRP-1A and with and the of with the the protein The to or to a The by the The and from the and of in Drosophila melanogaster and is from is to a in the binding of activity by the aconitase to and The in a of in the of of recombinant Drosophila IRP-1A or IRP-1B and an of the of to the of is used as the in used as a the aconitase is in and of IRP-1A and and IRP-1B to recombinant with in proteins with a of from by and and by a to The of of recombinant IRP-1A and IRP-1B The of IRP-1A and of protein the by protein IRP-1A and IRP-1B of IRP-1A and IRP-1B has to in the of the aconitase proteins as and IRP-1A and IRP-1B aconitase activity as purified The to a of recombinant with an and aconitase activity in the as purified recombinant IRP1 in a melanogaster is the to contain two cytosolic of recombinant IRP-1A and of recombinant IRP-1A and IRP-1B aconitase activity in The activity is as the in and of recombinant in is from with expression used to binding activity of IRP-1A and and IRP-1B and to and and Drosophila and IREs. of recombinant protein in of by in or to IRP-1A to the we bind to an recombinant IRP-1A to bind in Drosophila and in the of a and In IRP-1B not Drosophila or binding activity of IRP-1B the protein in or by and and and not binding and aconitase activity of recombinant IRP-1A and IRP-1B in to iron of recombinant or with and as of the with Drosophila and binding activity by The of the aconitase activity in a The activity is as the in and of recombinant binding activity the binding of IRP-1A to of and to The showed to the the of not the an binding activity IRP-1A with the binding activity of Drosophila to of IRP-1A binding to of Drosophila with of purified in the binding a of or with a in the with the of the of with of as purified from has aconitase activity and to with in and or in by a to with in the of iron has the purified The of iron with to is by of in of aconitase activity and in binding in with mammalian IRP1 In binding activity in with purified but aconitase activity of IRP-1B the of iron and the of to the regions of IRP-1A contain the binding of IRP-1B with from IRP-1A and to with in and purified as and of the purified recombinant proteins to and binding activity with the activity of to The and to bind and Drosophila with an activity of and The and not binding activity of purified protein the not of IRP-1A and IRP-1B in the we in we in and expression of the by of the of IRP-1A in a in a of binding activity of IRP-1B the aconitase activity of by in the of IRP-1A and by IRP-1B of proteins in with binding and aconitase of aconitase by the in activity to from the cytosolic the two proteins by IRP1 binding and aconitase activity of from of protein from of the with and by aconitase of the with of IRP-1B or in with in aconitase activity of the by aconitase the in aconitase activity is to a of cytosolic aconitase of the with IRP1 and IRP-1A and to IRP-1A and IRP-1B with a of the of expression and the of IRP-1A in In IRP-1B and the the two proteins we the of IRP-1A by expression of IRP-1A to a expression of IRP-1A in and not expression in to with or to the with of IRP-1A or IRP-1B in a in a and of IRP-1A and and IRP-1B to recombinant with in proteins with a of from by and and by a to The of of recombinant IRP-1A and IRP-1B The of IRP-1A and of protein the by protein IRP-1A and IRP-1B of IRP-1A and IRP-1B has to in the of the aconitase proteins as and IRP-1A and IRP-1B aconitase activity as purified The to a of recombinant with an and aconitase activity in the as purified recombinant IRP1 in a melanogaster is the to contain two cytosolic IRP-1A to the we bind to an recombinant IRP-1A to bind in Drosophila and in the of a and In IRP-1B not Drosophila or binding activity of IRP-1B the protein in or by and and and not the binding of IRP-1A to of and to The showed to the the of not the an binding activity IRP-1A with the binding activity of Drosophila to IRP-1A of with of as purified from has aconitase activity and to with in and or in by a to with in the of iron has the purified The of iron with to is by of in of aconitase activity and in binding in with mammalian IRP1 In binding activity in with purified but aconitase activity of IRP-1B the of iron and the of to the regions of IRP-1A contain the binding of IRP-1B with from IRP-1A and to with in and purified as and of the purified recombinant proteins to and binding activity with the activity of to The and to bind and Drosophila with an activity of and The and not binding activity of purified protein the not of IRP-1A and IRP-1B in the we in we in and expression of the by of the of IRP-1A in a in a of binding activity of IRP-1B the aconitase activity of by in the of IRP-1A and by IRP-1B of proteins in with binding and aconitase of aconitase by the in activity to from the cytosolic the two proteins by IRP1 IRP-1A and IRP-1B with a of the of expression and the of IRP-1A in In IRP-1B and the the two proteins we the of IRP-1A by expression of IRP-1A to a expression of IRP-1A in and not expression in to with or to the the of two to the of cytosolic or by in the melanogaster and the two proteins IRP-1A is to the mammalian as a cytosolic aconitase or an through the and of a IRP-1B is more to the cytosolic aconitase of is more ancient and IREs. in of IRP-1A and IRP-1B in the binding of IRP-1A in Drosophila and IRP-1A a evolutionary from a of to of IRP1 binding by the of the to of the and is by the The the and the IRP1 binding and in of the IRP1 is with of of IRP-1B with the IRP-1A binding activity to the of the IRP-1A protein of the of the genome of Drosophila and IRP-1A and IRP-1B in the two proteins the as in the two and in the two the two to of the two and the two we in of the protein of or in with regions in binding IRP1 in IRP-1A from two Drosophila in IRP-1B The IRP1 is in binding of in not in not in not in not in not melanogaster and not in not melanogaster and not in not in not in not in IRP-1B and not in not in IRP-1A and not in IRP-1B and not in not melanogaster and IRP-1B and not in not melanogaster and not in not in not in not in not in IRP-1A and IRP-1A and not in not in not melanogaster and not in not in not in not in not melanogaster and IRP-1B and IRP-1A and in a the IRP1 the IRP-1A and IRP-1B of not the binding the and in IRP-1B of in the In a in in a by a of and IRP-1B and in the The of is not and IRP-1B and with IRP1 the protein of IRP-1A and IRP-1B the of IRP1 the of the with IRP1 the in aconitase activity in binding with the in the IRP1 we Drosophila an to IRP-1A and IRP-1B the of the protein IRP-1A and IRP-1B contain an of a in in IRP-1B) as with the binding is to a an of from in IRP-1B the of in in IRP-1A is a of IRP-1B is in in to the In IRP-1A with the IRP1 in more IRP-1A and IRP1 to The two by to IRP-1A and IRP-1B and in IRP-1B) from the is to the of in IRP-1A an protein in to its of the protein in function in iron and in more the of proteins to the is contained in the and the by of genes and of proteins of function to the through of and of the by a of gene cytosolic aconitase to from and a of cytosolic aconitase two cytosolic in of the two cytosolic to in binding of the of is to as by the The is in the in the and regions not by the to a of a protein with a of an in an and a and a to the the of an gene is or the of to and the of to aconitase function in the is more ancient a of the protein in iron cells to in the and in the and in IRP1 control of the aconitase is in mammalian cells and the of is contained in an a of of we the in by gene of two cytosolic of the to bind to the the and the the to the of the of in or the of or in the as the evolutionary the has a in is the control of is an and the of a cytosolic to control the of iron in the In is the in is in a as to a with is the iron in cells and a target iron evolutionary an of in of the cytosolic as IRP2) and of its activity as an aconitase by of a is the in evolutionary terms is to IRP2 of control of IRP2 by and iron the dominant in mammalian iron the of two to the of cytosolic or by in the melanogaster and the two proteins IRP-1A is to the mammalian as a cytosolic aconitase or an through the and of a IRP-1B is more to the cytosolic aconitase of is more ancient and IREs. in of IRP-1A and IRP-1B in the binding of IRP-1A in Drosophila and IRP-1A a evolutionary from a of to of IRP1 binding by the of the to of the and is by the The the and the IRP1 binding and in of the IRP1 is with of of IRP-1B with the IRP-1A binding activity to the of the IRP-1A protein of the of the genome of Drosophila and IRP-1A and IRP-1B in the two proteins the as in the two and in the two the two to of the two and the two we in of the protein of or in with regions in binding IRP1 the IRP1 the IRP-1A and IRP-1B of not the binding the and in IRP-1B of in the In a in in a by a of and IRP-1B and in the The of is not IRP-1A and IRP-1B and with IRP1 the protein of IRP-1A and IRP-1B the of IRP1 the of the with IRP1 the in aconitase activity in binding with the in the IRP1 we Drosophila an to IRP-1A and IRP-1B the of the protein IRP-1A and IRP-1B contain an of a in in IRP-1B) as with the binding is to a an of from in IRP-1B the of in in IRP-1A is a of IRP-1B is in in to the In IRP-1A with the IRP1 in more IRP-1A and IRP1 to The two by to IRP-1A and IRP-1B and in IRP-1B) from the is to the of in IRP-1A an protein in to its of the protein in function in iron and in more the of proteins to the is contained in the and the by of genes and of proteins of function to the through of and of the by a of gene cytosolic aconitase to from and a of cytosolic aconitase two cytosolic in of the two cytosolic to in binding of the of is to as by the The is in the in the and regions not by the to a of a protein with a of an in an and a and a to the the of an gene is or the of to and the of to aconitase function in the is more ancient a of the protein in iron cells to in the and in the and in IRP1 control of the aconitase is in mammalian cells and the of is contained in an a of of we the in by gene of two cytosolic of the to bind to the the and the the to the of the of in or the of or in the as the evolutionary the has a in is the control of is an and the of a cytosolic to control the of iron in the In is the in is in a as to a with is the iron in cells and a target iron evolutionary an of in of the cytosolic as IRP2) and of its activity as an aconitase by of a is the in evolutionary terms is to IRP2 of control of IRP2 by and iron the dominant in mammalian iron with the aconitase and and of the

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.