Serine Phosphorylation of L-Selectin Regulates ERM Binding, Clustering, and Monocyte Protrusion in Transendothelial Migration
The migration of circulating leukocytes toward damaged tissue is absolutely fundamental to the inflammatory response, and transendothelial migration (TEM) describes the first cellular barrier that is breached in this process. Human CD14+ inflammatory monocytes express L-selectin, bestowing a non-can...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2019-09-01
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| Series: | Frontiers in Immunology |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fimmu.2019.02227/full |
| _version_ | 1811326361873154048 |
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| author | Abigail Newe Karolina Rzeniewicz Melanie König Carsten F. E. Schroer Justin Joachim Angela Rey-Gallardo Siewert J. Marrink Jürgen Deka Maddy Parsons Aleksandar Ivetic |
| author_facet | Abigail Newe Karolina Rzeniewicz Melanie König Carsten F. E. Schroer Justin Joachim Angela Rey-Gallardo Siewert J. Marrink Jürgen Deka Maddy Parsons Aleksandar Ivetic |
| author_sort | Abigail Newe |
| collection | DOAJ |
| description | The migration of circulating leukocytes toward damaged tissue is absolutely fundamental to the inflammatory response, and transendothelial migration (TEM) describes the first cellular barrier that is breached in this process. Human CD14+ inflammatory monocytes express L-selectin, bestowing a non-canonical role in invasion during TEM. In vivo evidence supports a role for L-selectin in regulating TEM and chemotaxis, but the intracellular mechanism is poorly understood. The ezrin-radixin-moesin (ERM) proteins anchor transmembrane proteins to the cortical actin-based cytoskeleton and additionally act as signaling adaptors. During TEM, the L-selectin tail within transmigrating pseudopods interacts first with ezrin to transduce signals for protrusion, followed by moesin to drive ectodomain shedding of L-selectin to limit protrusion. Collectively, interaction of L-selectin with ezrin and moesin fine-tunes monocyte protrusive behavior in TEM. Using FLIM/FRET approaches, we show that ERM binding is absolutely required for outside-in L-selectin clustering. The cytoplasmic tail of human L-selectin contains two serine (S) residues at positions 364 and 367, and here we show that they play divergent roles in regulating ERM binding. Phospho-S364 blocks direct interaction with ERM, whereas molecular modeling suggests phospho-S367 likely drives desorption of the L-selectin tail from the inner leaflet of the plasma membrane to potentiate ERM binding. Serine-to-alanine mutagenesis of S367, but not S364, significantly reduced monocyte protrusive behavior in TEM under flow conditions. Our data propose a model whereby L-selectin tail desorption from the inner leaflet of the plasma membrane and ERM binding are two separable steps that collectively regulate protrusive behavior in TEM. |
| first_indexed | 2024-04-13T14:48:23Z |
| format | Article |
| id | doaj.art-eccfc0ffef7e4d0e8d2c08cc4808aab8 |
| institution | Directory Open Access Journal |
| issn | 1664-3224 |
| language | English |
| last_indexed | 2024-04-13T14:48:23Z |
| publishDate | 2019-09-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Immunology |
| spelling | doaj.art-eccfc0ffef7e4d0e8d2c08cc4808aab82022-12-22T02:42:41ZengFrontiers Media S.A.Frontiers in Immunology1664-32242019-09-011010.3389/fimmu.2019.02227468377Serine Phosphorylation of L-Selectin Regulates ERM Binding, Clustering, and Monocyte Protrusion in Transendothelial MigrationAbigail Newe0Karolina Rzeniewicz1Melanie König2Carsten F. E. Schroer3Justin Joachim4Angela Rey-Gallardo5Siewert J. Marrink6Jürgen Deka7Maddy Parsons8Aleksandar Ivetic9BHF Centre of Research Excellence, James Black Centre, King's College London, London, United KingdomBHF Centre of Research Excellence, James Black Centre, King's College London, London, United KingdomGroningen Biomolecular Sciences and Biotechnology Institute, Groningen, NetherlandsGroningen Biomolecular Sciences and Biotechnology Institute, Groningen, NetherlandsBHF Centre of Research Excellence, James Black Centre, King's College London, London, United KingdomBHF Centre of Research Excellence, James Black Centre, King's College London, London, United KingdomGroningen Biomolecular Sciences and Biotechnology Institute, Groningen, NetherlandsEuropean Molecular Biology Laboratory, Heidelberg, GermanyRandall Centre for Cell and Molecular Biophysics, King's College London, London, United KingdomBHF Centre of Research Excellence, James Black Centre, King's College London, London, United KingdomThe migration of circulating leukocytes toward damaged tissue is absolutely fundamental to the inflammatory response, and transendothelial migration (TEM) describes the first cellular barrier that is breached in this process. Human CD14+ inflammatory monocytes express L-selectin, bestowing a non-canonical role in invasion during TEM. In vivo evidence supports a role for L-selectin in regulating TEM and chemotaxis, but the intracellular mechanism is poorly understood. The ezrin-radixin-moesin (ERM) proteins anchor transmembrane proteins to the cortical actin-based cytoskeleton and additionally act as signaling adaptors. During TEM, the L-selectin tail within transmigrating pseudopods interacts first with ezrin to transduce signals for protrusion, followed by moesin to drive ectodomain shedding of L-selectin to limit protrusion. Collectively, interaction of L-selectin with ezrin and moesin fine-tunes monocyte protrusive behavior in TEM. Using FLIM/FRET approaches, we show that ERM binding is absolutely required for outside-in L-selectin clustering. The cytoplasmic tail of human L-selectin contains two serine (S) residues at positions 364 and 367, and here we show that they play divergent roles in regulating ERM binding. Phospho-S364 blocks direct interaction with ERM, whereas molecular modeling suggests phospho-S367 likely drives desorption of the L-selectin tail from the inner leaflet of the plasma membrane to potentiate ERM binding. Serine-to-alanine mutagenesis of S367, but not S364, significantly reduced monocyte protrusive behavior in TEM under flow conditions. Our data propose a model whereby L-selectin tail desorption from the inner leaflet of the plasma membrane and ERM binding are two separable steps that collectively regulate protrusive behavior in TEM.https://www.frontiersin.org/article/10.3389/fimmu.2019.02227/fullförster resonance energy transfer (FRET)fluorescence lifetime imaging microscopy (FLIM)molecular dynamicsextravasationdiapedesis |
| spellingShingle | Abigail Newe Karolina Rzeniewicz Melanie König Carsten F. E. Schroer Justin Joachim Angela Rey-Gallardo Siewert J. Marrink Jürgen Deka Maddy Parsons Aleksandar Ivetic Serine Phosphorylation of L-Selectin Regulates ERM Binding, Clustering, and Monocyte Protrusion in Transendothelial Migration Frontiers in Immunology förster resonance energy transfer (FRET) fluorescence lifetime imaging microscopy (FLIM) molecular dynamics extravasation diapedesis |
| title | Serine Phosphorylation of L-Selectin Regulates ERM Binding, Clustering, and Monocyte Protrusion in Transendothelial Migration |
| title_full | Serine Phosphorylation of L-Selectin Regulates ERM Binding, Clustering, and Monocyte Protrusion in Transendothelial Migration |
| title_fullStr | Serine Phosphorylation of L-Selectin Regulates ERM Binding, Clustering, and Monocyte Protrusion in Transendothelial Migration |
| title_full_unstemmed | Serine Phosphorylation of L-Selectin Regulates ERM Binding, Clustering, and Monocyte Protrusion in Transendothelial Migration |
| title_short | Serine Phosphorylation of L-Selectin Regulates ERM Binding, Clustering, and Monocyte Protrusion in Transendothelial Migration |
| title_sort | serine phosphorylation of l selectin regulates erm binding clustering and monocyte protrusion in transendothelial migration |
| topic | förster resonance energy transfer (FRET) fluorescence lifetime imaging microscopy (FLIM) molecular dynamics extravasation diapedesis |
| url | https://www.frontiersin.org/article/10.3389/fimmu.2019.02227/full |
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