title: Moesin controls clathrin-mediated S1PR1 internalization in T cells.
abstract: The lipid mediator sphingosine 1-phosphate (S1P) regulates a wide range of cellular activities, including vascular maturation, angiogenesis, and immune-cell trafficking. Among the five known receptors for S1P (S1PR1-S1PR5), S1PR1 is a critical regulator of lymphocyte trafficking: its signaling is required for lymphocyte egress from lymphoid organs, while its down-modulation by agonist-induced internalization is a prerequisite for lymphocyte entry into lymphoid organs from the bloodstream. Despite the importance of S1PR1 down-regulation in determining lymphocyte behavior, the molecular mechanism of its internalization in lymphocytes has not been defined. Here we show that agonist-induced S1PR1 internalization in T cells occurs via clathrin-mediated endocytosis and is regulated by moesin, an ezrin-radixin-moesin (ERM) family member. In S1P-stimulated T cells, S1PR1 relocalized within clathrin-coated vesicles (CCVs) and early endosomes, and S1PR1 internalization was blocked when clathrin was pharmacologically inhibited. Stimulating moesin-deficient T cells with S1P failed to induce S1PR1 internalization and CCV formation. Furthermore, treating moesin-deficient mice with FTY720, an S1P receptor agonist known to internalize S1PR1, caused delayed lymphopenia, and lymphocytes isolated from FTY720-treated moesin-deficient mice still responded to S1P ex vivo in chemotaxis assays. These results reveal a novel role for moesin in regulating clathrin-dependent S1PR1 internalization through CCV formation.
authors.affiliation: Center for Innovation in Immunoregulative Technology and Therapeutics, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Nomachi
authors.affiliation: Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Yoshinaga
authors.affiliation: Mechanobiology Institute, Singapore, Singapore.
authors.forename: Jaron
authors.initials: J
authors.lastname: Liu
authors.affiliation: Mechanobiology Institute, Singapore, Singapore ; Department of Bioengineering, National University of Singapore, Singapore, Singapore.
authors.forename: Pakorn
authors.initials: P
authors.lastname: Kanchanawong
authors.affiliation: Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Tohyama
authors.affiliation: Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Dean
authors.initials: D
authors.lastname: Thumkeo
authors.affiliation: Center for Innovation in Immunoregulative Technology and Therapeutics, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Center for Innovation in Immunoregulative Technology and Therapeutics, Kyoto University Graduate School of Medicine, Kyoto, Japan ; Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Shuh
authors.initials: S
authors.lastname: Narumiya
authors.affiliation: Department of Fundamental Biosciences, Shiga University of Medical Science, Otsu, Shiga, Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Hirata
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte / Q000235:genetics; D022163:Clathrin-Coated Vesicles / Q000378:metabolism*; D004705:Endocytosis / Q000235:genetics*; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008840:Microfilament Proteins / Q000502:physiology*; D049349:Receptors, Lysosphingolipid / Q000378:metabolism*; D000081025:Sphingosine-1-Phosphate Receptors
chemical_list: D008840:Microfilament Proteins; D049349:Receptors, Lysosphingolipid; C556330:S1pr1 protein, mouse; D000081025:Sphingosine-1-Phosphate Receptors; C071058:moesin