KINE 2475 Lecture Notes - Lecture 18: Iron-Responsive Element-Binding Protein, Transferrin Receptor, Ferritin
13 Jan 2020
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Document Summary
Clathrin forms a contractile structure (pull in on itself to form a clathrin coated put. Clathrin forms and endosome: tfr not degraded in lysosome, free transferrin is called apo transferrin- released to surface, endosome vs clathrin pit. Proteins are pumped into endosomes (use energy) net result: inside of endosome becomes acidic (low ph) When fe low, tfr mrna goes up; when fe high, tfr mrna is not stabilized. Iron-responsive elements (ire: within mrnas of ferritin & transferrin receptors & aconitase (enzyme that catalyzes stero-specific isomerase) , nucleotide sequences have been identified which defines a binding site for iron responsive proteins. Binding of these alters translational efficiency of of these mrnas in opposite ways- allows coordination of iron stores & transporters. Ire is conserved loop which is bounded to iron response proteins. Ire found in untranslated regions: ferritin contains ire in 5"utr. When iron concentration low, irps bind to ire in ferritin mrna and causes reduced translation rates.
