Igf1 - alec: Difference between revisions

<StructureSection load='1gzy' size='340' side='right' caption='Caption for this structure' scene=''>

The protein '''Insulin-like Growth Factor 1 (IGF-1)''' is a liver protein that shows many similarities to Insulin. The two molecules have around sixty percent similarities in their structures, and are released under similar circumstances into the bloodstream. IGF-1 acts as the main growth factor to insulin, acting as the nutrition for cells. The similarities between the two molecules allows for easy transportation of IGF-1 through the bloodstream. As insulin is released into the blood upon hyperglycemic conditions, IGF-1 is released upon excess protein intake and will transport the proteins to cells where it can be used for growth.  IGF-1 release can also be stimulated by secretion of Growth Hormone, which induces the protein to deliver nutrients to cells. This process occurs extensively throughout puberty of children. Additionally, after puberty, IGF-1 can be regulated by the release of GH but not to the level of that during puberty and can regularly be secreted without GH stimulus. There have been recent studies showing the biological necessity for IGF-1, as well as the costs of having low levels of this protein which range from reduced cell growth to dysfunctions of particular cells.  <ref name = 'Clemmons'> PMID: 22682639 </ref>

 

The molecular structure of <scene name='81/814755/Igf1_structure2/2'>IGF-1</scene> tell us many things about the protein itself. Upon inspection of the structure of the IGF-1 protein side by side with <scene name='81/814755/Insulin_structure2/2'>insulin</scene>, there are three noticeable alpha helixes that are almost identical throughout the backbones of the molecules. The IGF-1 protein, being a relatively small molecule with only sixty-nine amino acids, is larger than the insulin molecule (which only has a 51 amino acid sequence). Because of the relatively small size of these molecules, they are easily transported out of the liver and pancreas into the blood and throughout the body. However, unlike insulin which is produced and stored as a hexamer containing six insulin monomers, IGF-1 is produced and stored as a monomer. Because of the structural similarities to insulin, upon the release of IGF-1 from the liver, it can bind to its own transmembrane receptors called '''<scene name='81/814755/Igf-1r/2'>IGF-1 receptors</scene>''' (IGF-1R) on cells but can also bind to the insulin receptor depending on biological conditions. Because of their structural similarities, in conditions where insulin is not present or in reduced amounts IGF-1 can bind to both insulin receptors and its own. This also works for insulin, where in conditions of low IGF-1, it can bind to both its own receptors and IGF-1R.