Phosphatidylinositol and phosphatidic acid transport between the ER and plasma membrane during PLC activation requires the Nir2 protein
| Autor: | Maria Luisa Guzman-Hernandez, Nicolas Echeverria, Yeun Ju Kim, Eva Wisniewski, Tamas Balla |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Phosphatidic Acids Biology Endoplasmic Reticulum Phosphatidylinositols Biochemistry Article Cell membrane 03 medical and health sciences chemistry.chemical_compound Calcium-binding protein medicine Animals Humans Phosphatidylinositol Diacylglycerol kinase Phospholipase C Endoplasmic reticulum Calcium-Binding Proteins Cell Membrane Biological Transport Phosphatidic acid Cell biology 030104 developmental biology medicine.anatomical_structure chemistry Type C Phospholipases Phosphorylation |
| Zdroj: | Biochemical Society Transactions. 44:197-201 |
| ISSN: | 1470-8752 0300-5127 |
| Popis: | Phospholipase C (PLC)-mediated hydrolysis of the limited pool of plasma membrane (PM) phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] requires replenishment from a larger pool of phosphatidylinositol (PtdIns) via sequential phosphorylation by PtdIns 4-kinases and phosphatidylinositol 4-phosphate (PtdIns4P) 5-kinases. Since PtdIns is synthesized in the endoplasmic reticulum (ER) and PtdIns(4,5)P2 is generated in the PM, it has been postulated that PtdIns transfer proteins (PITPs) provide the means for this lipid transfer function. Recent studies identified the large PITP protein, Nir2 as important for PtdIns transfer from the ER to the PM. It was also found that Nir2 was required for the transfer of phosphatidic acid (PtdOH) from the PM to the ER. In Nir2-depleted cells, activation of PLC leads to PtdOH accumulation in the PM and PtdIns synthesis becomes severely impaired. In quiescent cells, Nir2 is localized to the ER via interaction of its FFAT domain with ER-bound VAMP-associated proteins VAP-A and–B. After PLC activation, Nir2 also binds to the PM via interaction of its C-terminal domains with diacylglycerol (DAG) and PtdOH. Through these interactions, Nir2 functions in ER–PM contact zones. Mutations in VAP-B that have been identified in familial forms of amyotrophic lateral sclerosis (ALS or Lou-Gehrig's disease) cause aggregation of the VAP-B protein, which then impairs its binding to several proteins, including Nir2. These findings have shed new lights on the importance of non-vesicular lipid transfer of PtdIns and PtdOH in ER–PM contact zones with a possible link to a devastating human disease. |
| Databáze: | OpenAIRE |
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