Hepatic Synthesis, Maturation and Complex Formation between Retinol-Binding Protein and Transthyretin
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Sancia Gaetani
Abstract
The retinol/retinol-binding protein/transthyretin complex, that carries and delivers hydrophobic retinol molecules to target cells, is assembled in the hepatocyte endoplasmic reticulum. In this paper, we review data related to events that lead to the formation of this complex, including transthyretin oligomerization and retinol-binding protein secretion. Our studies on transthyretin oligomerization have demonstrated that cleavage of signal peptide and the environment of endoplasmic reticulum influence transthyretin oligomerization. In vitro, mutated transthyretin without signal sequence fails to form dimers, while wild-type transthyretin is translocated into the microsomes where it forms dimers and small amounts of tetramers. In vivo, tetramers were detected in HepG2 cells but not in transfected Cos cells, suggesting that tissue-specific factors affect tetramer stability. In vitamin A deficiency, retinol-binding protein secretion is blocked and the protein accumulates in the endoplasmic reticulum, from where it is promptly released after retinol repletion. We use MMH cells to identify factors involved in complex formation, retention and secretion, the crucial steps to understand the molecular mechanisms underlying vitamin A homeostasis. In parallel, studies on vitamin A transport in fish are in progress; retinolbinding protein and transthyretin have already been characterized in different fish species.
Copyright © 2002 by Walter de Gruyter GmbH & Co. KG
Artikel in diesem Heft
- Author Index
- Subject Index
- Contents
- Historical Aspects and Perspectives in Transthyretin Research
- Transthyretin from Discovery to Now
- The Evolution of Transthyretin Synthesis in Vertebrate Liver, in Primitive Eukaryotes and in Bacteria
- The Evolution of Transthyretin Synthesis in the Choroid Plexus
- Hepatic Synthesis, Maturation and Complex Formation between Retinol-Binding Protein and Transthyretin
- Synthesis and Structural Analysis of the N-Terminal Domain of the Thyroid Hormone-Binding Protein Transthyretin
- Three-Dimensional Structure of the Transthyretin-Retinol-Binding Protein Complex
- Mechanisms of Molecular Recognition: Crystal Structure Analysis of Human and Rat Transthyretin Inhibitor Complexes
- Transthyretin in Fish: State of the Art
- The Effects of Endocrine-Disrupting Chemicals on Thyroid Hormone Binding to Xenopus laevis Transthyretin and Thyroid Hormone Receptor
- Clinical Picture and Outcome of Transthyretin-Related Familial Amyloid Polyneuropathy (FAP) in Japanese Patients
- Laboratory Assessment of Transthyretin Amyloidosis
- Amyloid: Morphology and Toxicity
- Historical Overview of Analytical Methods for the Measurement of Transthyretin
- Nutritional Regulation of Visceral Markers in Rat Liver and Cultured Hepatoma Cells
- Significance of Transthyretin in Protein Metabolism
- Transthyretin as a Thyroid Hormone Carrier: Function Revisited
- The Molar Ratio of Retinol-Binding Protein to Transthyretin in the Assessment of Vitamin A Status in Adults. Proposal of a Cut-off Point
- Observations with Regard to the National Kidney Foundation K/DOQI Clinical Practice Guidelines Concerning Serum Transthyretin in Chronic Renal Failure
- Metabolism and Clinical Interest of Serum Transthyretin (Prealbumin) in Dialysis Patients
- Protein Status in Pancreatitis – Transthyretin Is a Sensitive Biomarker of Malnutrition in Acute and Chronic Pancreatitis
- Assessment of Nutritional Status in Organ Transplant: Is Transthyretin a Reliable Indicator?
- Body Composition and Nutritional Parameters in HIV and AIDS Patients
- C-Reactive Protein to Transthyretin Ratio for the Early Diagnosis and Follow-up of Postoperative Infection
- The Prognostic Value of Nutritional and Inflammatory Indices in Critically Ill Patients with Acute Respiratory Failure
- Transthyretin: Its Response to Malnutrition and Stress Injury. Clinical Usefulness and Economic Implications
- Transthyretin Measurement as a Screening Tool for Protein Calorie Malnutrition in Emergency Hospital Admissions
- Outcomes of Continuous Process Improvement of a Nutritional Care Program Incorporating TTR Measurement
- The Role of Visceral Protein Markers in Protein Calorie Malnutrition
- Acknowledgement
- Meetings
Artikel in diesem Heft
- Author Index
- Subject Index
- Contents
- Historical Aspects and Perspectives in Transthyretin Research
- Transthyretin from Discovery to Now
- The Evolution of Transthyretin Synthesis in Vertebrate Liver, in Primitive Eukaryotes and in Bacteria
- The Evolution of Transthyretin Synthesis in the Choroid Plexus
- Hepatic Synthesis, Maturation and Complex Formation between Retinol-Binding Protein and Transthyretin
- Synthesis and Structural Analysis of the N-Terminal Domain of the Thyroid Hormone-Binding Protein Transthyretin
- Three-Dimensional Structure of the Transthyretin-Retinol-Binding Protein Complex
- Mechanisms of Molecular Recognition: Crystal Structure Analysis of Human and Rat Transthyretin Inhibitor Complexes
- Transthyretin in Fish: State of the Art
- The Effects of Endocrine-Disrupting Chemicals on Thyroid Hormone Binding to Xenopus laevis Transthyretin and Thyroid Hormone Receptor
- Clinical Picture and Outcome of Transthyretin-Related Familial Amyloid Polyneuropathy (FAP) in Japanese Patients
- Laboratory Assessment of Transthyretin Amyloidosis
- Amyloid: Morphology and Toxicity
- Historical Overview of Analytical Methods for the Measurement of Transthyretin
- Nutritional Regulation of Visceral Markers in Rat Liver and Cultured Hepatoma Cells
- Significance of Transthyretin in Protein Metabolism
- Transthyretin as a Thyroid Hormone Carrier: Function Revisited
- The Molar Ratio of Retinol-Binding Protein to Transthyretin in the Assessment of Vitamin A Status in Adults. Proposal of a Cut-off Point
- Observations with Regard to the National Kidney Foundation K/DOQI Clinical Practice Guidelines Concerning Serum Transthyretin in Chronic Renal Failure
- Metabolism and Clinical Interest of Serum Transthyretin (Prealbumin) in Dialysis Patients
- Protein Status in Pancreatitis – Transthyretin Is a Sensitive Biomarker of Malnutrition in Acute and Chronic Pancreatitis
- Assessment of Nutritional Status in Organ Transplant: Is Transthyretin a Reliable Indicator?
- Body Composition and Nutritional Parameters in HIV and AIDS Patients
- C-Reactive Protein to Transthyretin Ratio for the Early Diagnosis and Follow-up of Postoperative Infection
- The Prognostic Value of Nutritional and Inflammatory Indices in Critically Ill Patients with Acute Respiratory Failure
- Transthyretin: Its Response to Malnutrition and Stress Injury. Clinical Usefulness and Economic Implications
- Transthyretin Measurement as a Screening Tool for Protein Calorie Malnutrition in Emergency Hospital Admissions
- Outcomes of Continuous Process Improvement of a Nutritional Care Program Incorporating TTR Measurement
- The Role of Visceral Protein Markers in Protein Calorie Malnutrition
- Acknowledgement
- Meetings
