腸内葉酸トランスポーターの特定と,遺伝的な葉酸吸収不良の分子基礎
Andong Qiu1, Michaela Jansen, Antoinette Sakaris
1Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
Cell
|November 30, 2006
まとめ
科学者たちは,小腸内の栄養素吸収に不可欠な新しい高親和性葉酸トランスポーターを発見しました. この陽子結合葉酸トランスポーター (PCFT) は葉酸ホメオスタシスに不可欠であり,その機能不全は遺伝的な葉酸マラ吸収を引き起こす.
科学分野:
- 栄養バイオケミストリー
- 人間の生理学 人間生理学
- 分子遺伝学 分子遺伝学
背景:
- 葉酸は,DNA合成と表遺伝的調節を含む細胞のプロセスにとって不可欠な微量栄養素です.
- 葉酸の吸収は主に酸性条件下で小腸上部で起こりますが,輸送機構はほとんど定義されていません.
- 以前の研究で,低親和性,pHに依存しない輸送特性を持つヘムキャリアタンパク質 (HCP1) が特定されました.
研究 の 目的:
- 人間の小腸上部の葉酸吸収の分子機構を特定し,特徴づけること.
- 葉酸ホメオスタシスと遺伝性葉酸マラ吸収における特定のトランスポーターの役割を調査する.
主な方法:
- ヒトの腸内細胞における新しい高親和性,pH依存の葉酸トランスポーターの識別と機能的特徴付け.
- 遺伝的葉酸吸収不良に罹患する家族における特定された遺伝子の機能喪失変異の分析.
- 以前に特定されたヘムキャリアタンパク質1 (HCP1) の葉酸輸送における役割について再評価.
主要な成果:
- ヒトのプロトン結合型,高親和性葉酸トランスポーター (PCFT) が特定され,低pHで腸および他の細胞タイプで葉酸の吸収を担当しました.
- PCFT遺伝子の機能喪失変異が,研究された1つの家族における遺伝的葉酸吸収不良の原因であると確認されました.
- この研究では,PCFT/HCP1の主な機能は,葉酸ホメオスタシスに不可欠な,陽子結合葉酸輸送であることが明らかになった.
結論:
- 陽子結合葉酸トランスポーター (PCFT/HCP1) は,ヒトの腸内の葉酸の効率的な吸収に不可欠です.
- PCFT/HCP1の欠陥は,遺伝的な葉酸の吸収不良につながり,ヒトの栄養における葉酸の重要性を強調しています.
- この発見は,PCFT/HCP1遺伝子産物の主要な役割を,ヘム媒介体から重要な葉酸媒介体へと再定義する.
関連する概念動画
Drug Absorption Mechanism: Carrier-Mediated Membrane Transport
Certain large, lipid-insoluble drug molecules that resemble amino acids, peptides, or glucose, require specialized carrier proteins to facilitate their diffusion across cell membranes. This transport can occur through either facilitated diffusion, which does not require energy input, or active transport, which does require energy input.
Facilitated diffusion is a passive process that utilizes human Solute Carrier (SLC) transporters. These transporters bind to the drug, undergo structural...
Facilitated diffusion is a passive process that utilizes human Solute Carrier (SLC) transporters. These transporters bind to the drug, undergo structural...
Inborn Errors of Metabolism
Phenylketonuria (PKU) is a protein metabolism disorder characterized by high blood levels of the amino acid phenylalanine. This results from a mutation in the gene responsible for phenylalanine hydroxylase, an enzyme that converts phenylalanine into tyrosine. When this enzyme is deficient, phenylalanine builds up in the blood, leading to symptoms such as vomiting, rashes, seizures, growth deficiency, and severe mental retardation. An early diagnosis and a diet restricting phenylalanine intake...
Factors Influencing Drug Absorption: Disease States and Pharmacology
Multiple disease states can significantly influence the oral drug absorption process by affecting blood flow and the functionality of the gastrointestinal (GI) system. Various GI diseases, including conditions that alter GI motility, such as diarrhea, decreased acid secretions (achlorhydria), and infections, have been associated with reduced drug absorption.
Substances such as alcohol and specific drugs, including antineoplastics, can also negatively impact drug absorption. For instance,...
Substances such as alcohol and specific drugs, including antineoplastics, can also negatively impact drug absorption. For instance,...
Pharmacogenomics: Identification of New Drug Targets
Advances in genomics have profoundly influenced drug discovery by increasing both the speed and accuracy of pharmaceutical development. Pharmacogenomics, which examines how genetic variation influences drug response, facilitates the identification of novel therapeutic targets and enables patient stratification for personalized treatment. These strategies contribute to improved drug efficacy, minimized adverse effects, and more efficient clinical trial design.Mapping genetic differences...
Esophageal Achalasia
Esophageal achalasia is a chronic neurogenic disorder characterized by impaired relaxation of the lower esophageal sphincter (LES) and absent or ineffective peristalsis in the distal esophagus. This leads to a functional obstruction without a physical blockage, despite significant disruption of esophageal motility.EtiologyAchalasia is caused by degeneration of the myenteric (Auerbach's) plexus, specifically the loss of inhibitory ganglion cells that produce vasoactive intestinal peptide (VIP)...
Inflammatory Bowel Disease III: Crohn's Disease
Crohn’s disease is a chronic, relapsing form of inflammatory bowel disease characterized by segmental, transmural inflammation that can affect any part of the gastrointestinal tract. Its pathogenesis arises from a combination of genetic susceptibility, environmental exposures, epithelial barrier dysfunction, and immune dysregulation. Together, these factors lead to an exaggerated immune response against components of the gut microbiome.Genetic and Environmental InfluencesMultiple genetic...


