BIOM 3200 Lecture Notes - Lecture 4: Red Hair, Melanocortin 4 Receptor, Opioid Peptide
4 Feb 2017
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Document Summary
Acth is cut from pomc parent molecule. 13 components of the melanocortinin system (plus 1 opioid) 4 posttranslational peptide products: a-melanocyte, b-melanocyte, g-melanocyte, acth. 5 receptors (7-membrane g-coupled protein receptors: mc1r, mc2r, mc3r, mc4r, mc5r. 2 antagonists: agouti, agouti related protein agrp. Opioid peptide is b-endorphin: form the pituitary, blocks pain: not a component but can be cleaved off of pomc. Different pomc peptides produce different cell types. Provides latitude control of many physiological functions by same prohormone. A-msh: when produce in the brain it inhibits food intake. In skin it acts on melanocytes; influencing skin colour in humans and coat colour in animals. Mcr: adrenal, skin, brain, penis etc. Mutation results in change of sexual function/dysfunction. A mutation in mcr4 can trigger early onset obesity. How a-msh increases brown/black pigment in skin. Normal: bind receptor, activate signal pathways, g-protein coupled receptors, camp, Pka, creb: synthesis of mitf, microphthalmia-associated transcription factor, transcription tyr, dct.
