{"id":999,"date":"2017-10-26T17:25:23","date_gmt":"2017-10-26T17:25:23","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/sunynutrition\/?post_type=chapter&p=999"},"modified":"2017-10-31T16:46:58","modified_gmt":"2017-10-31T16:46:58","slug":"12-63-vitamin-a-nuclear-receptors","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/atd-herkimer-nutrition\/chapter\/12-63-vitamin-a-nuclear-receptors\/","title":{"raw":"12.63 Vitamin A Nuclear Receptors","rendered":"12.63 Vitamin A Nuclear Receptors"},"content":{"raw":"
\r\n\r\nVitamin A, like vitamin D, has a nuclear receptor. Vitamin A technically has two nuclear receptors, the retinoic acid receptors (RARs) and retinoid X receptors (RXRs). Vitamin A, like polyunsaturated fatty acids, can be found in trans and cis forms, depending on the conformation of its double bonds. The ligand for RARs is all-trans-retinoic acid, and the ligand for RXRs is 9-cis retinoic acid.\r\n\r\nAs shown in the figure below, all-trans retinol is brought to the cell by RBP and TTR. All-trans retinol is converted to all-trans-retinal, and then to all-trans-retinoic acid. RAR and RXR are paired, or dimerized, on the retinoic acid response element (RARE) in the promoter region of target genes. The binding of all-trans retinoic acid causes the transcription and ultimately the translation of target proteins. This is why all-trans-retinoic acid is the active form of vitamin A because it is the ligand for RARs, leading to many of the biologic effects attributed to vitamin A.\r\n
\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"1008\"]\"\" Figure 12.631 All-trans retinoic acid and retinoid X receptors[\/caption]\r\n\r\n<\/div>\r\n\r\n\r\nNo References<\/b>\r\n\r\n<\/div>","rendered":"
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Vitamin A, like vitamin D, has a nuclear receptor. Vitamin A technically has two nuclear receptors, the retinoic acid receptors (RARs) and retinoid X receptors (RXRs). Vitamin A, like polyunsaturated fatty acids, can be found in trans and cis forms, depending on the conformation of its double bonds. The ligand for RARs is all-trans-retinoic acid, and the ligand for RXRs is 9-cis retinoic acid.<\/p>\n

As shown in the figure below, all-trans retinol is brought to the cell by RBP and TTR. All-trans retinol is converted to all-trans-retinal, and then to all-trans-retinoic acid. RAR and RXR are paired, or dimerized, on the retinoic acid response element (RARE) in the promoter region of target genes. The binding of all-trans retinoic acid causes the transcription and ultimately the translation of target proteins. This is why all-trans-retinoic acid is the active form of vitamin A because it is the ligand for RARs, leading to many of the biologic effects attributed to vitamin A.<\/p>\n

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Figure 12.631 All-trans retinoic acid and retinoid X receptors<\/p>\n<\/div>\n<\/div>\n

No References<\/b><\/p>\n<\/div>\n\n\t\t\t

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