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Novel Roles for Phosphoinositide Signaling in alpha-Granule Biogenesis

磷酸肌醇信号传导在 α 颗粒生物发生中的新作用

基本信息

批准号：
9884351
负责人：
CHARLES S. ABRAMS
金额：
$ 11.01万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-02-01 至 2020-08-17
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9884351
关键词：
Address Affect Alpha Granule Binding Binding Proteins Biochemical Biogenesis Biology Blood Blood Cells Blood Platelets Blood coagulation Bone Marrow Cell membrane Cells Collaborations Cytoplasm Cytoplasmic Granules Data Defect Development Environment Fatty Acids GOLPH3 gene Golgi Apparatus Growth Factor Hand Hematopoiesis Hematopoietic stem cells Human Hydrophobicity Impairment Indiana Individual Inflammation Knock-out Left Link Maintenance Mediating Megakaryocytes Megakaryocytopoieses Membrane Morphology Multivesicular Body Mus Mutate Mutation Myocardial Infarction Neurons Patients Phenotype Phosphatidylinositol Transfer Protein Phosphatidylinositols Phospholipids Platelet Activation Play Process Production Property Protein Family Protein Isoforms Proteins Publications Publishing Regulation Role Second Messenger Systems Signal Pathway Signal Transduction Stroke Syndrome Testing Thrombosis Transforming Growth Factor beta Transmembrane Transport Universities aqueous cytokine human disease in vivo member monomer novel protein transport recruit trafficking trans-Golgi Network

项目摘要

Project Summary Phosphorylated phosphatidylinositols (phosphoinositides) are a type of membrane bound phospholipid that impact multiple diverse processes required for megakaryopoiesis and the activation of platelets. We have recently published in Developmental Cell that phosphoinositides in neuronal cells initiate intracellular trafficking by recruiting effector proteins such as GOLPH3 that are involved in vesicular fusion and budding of plasma membranes during Golgi biogenesis. Since megakaryocyte α-granules are derived from the trans-Golgi network and Multi-Vesicular Bodies, I hypothesize that phosphoinositide signaling is necessary for the intracellular trafficking required for the biogenesis of α-granules. PhosphatidylInositol Transfer Proteins (PITPs) are members of a small protein family that bind and transfer phosphoinositide monomers from one cellular compartment to another and thereby enable phosphoinositide synthesis. We have made the unexpected observation that the two predominant PITP isoforms found within megakaryocytes, PITPα and PITPβ play previously unrecognized but essential roles in the trafficking of cargo from the Multi-Vesicular Body to α-granules. Loss of PITP-mediated phosphoinositide synthesis produces morphologic defects similar to what is seen in humans with Gray Platelet Syndrome. The overall hypothesis of this Proposal is that phosphoinositide signaling mediated by PITPs is necessary for the membrane dynamics and protein trafficking required for the biogenesis and maintenance of megakaryocyte α-granules. In Aim 1 of the Project, we will rigorously analyze the discrete biochemical properties of individual PITP isoforms in megakaryocytes. Our preliminary data shows that the two PITP isoforms control phosphoinositide signaling through biochemically distinct mechanisms. In Aim 2, we will determine how phosphoinositide signaling contributes to alpha granule biogenesis and function. We will test the hypothesis that phosphoinositide synthesis within discrete microdomains of megakaryocytes and platelets regulates effector proteins such as NBEAL2 (the mutated protein responsible for Gray Platelet Syndrome). This signaling cascade modulates NBEAL2’s ability to mediate membrane dynamics and protein trafficking. We will also analyze in detail the functional roles of α-granules with ex vivo rheologic and ultramicroscopy studies, in vivo thrombosis studies, and in vivo inflammation studies.

项目总结