Sandbox Reserved 427: Difference between revisions
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===Introduction=== | ===Introduction=== | ||
Insulin receptor | |||
ABOUT | |||
-tyrosine kinase (ligand-activated receptor kinase) | |||
-expressed at cell surface as homodimers composed of alpha/beta monomers | |||
-disulfide-linked ectodomain dimer - folded over conformation places ligands in correct relative positions ('''green scene''') | |||
-mediate activity by addition of phophate to tyrosines on specific proteins in cell | |||
-found in organisms from cnidarians and insects to humans | |||
-in humans essential for maintaining glucose levels | |||
-also has role in growth and development (insulin growth factor II) | |||
-signal through IGF2 to mediate embryonic growth (Kitamura et al) | |||
FUNCTION | |||
-insulin receptor substrate 1 (IRS-1) binding leads to increase in high affinity glucose transporter (Glut4) molecules on the other membrane of cell (muscles, adipose) | |||
-leads to increased glu uptake (Glut4 mediates transport of glu into cell) | |||
<scene name='Sandbox_Reserved_427/Practice/1'>practice scene</scene> | |||
DISEASE | |||
-decreased insulin resceptor signalling (aka insulin insensitivity)leads to diabetes mellitus type 2 | |||
- cells unable to take up glu => hyperglycemia (increased circulating glucose) | |||
-aka non-insulin-dependent or adult onset diabetes | |||
-beleived to be caused by obesity and genetic predisposition | |||
-managed with dietary and lifestyle modifications | |||
-mutations in both copies of the insulin receptor gene causes Donohue syndrome (leprechaunism) | |||
-autosomal recessive; results in totally non-functional insulin receptor | |||
-results in distorted facial features, growth redardation and often death within a year | |||
===Overall Structure=== | ===Overall Structure=== | ||
