The actin-based motor protein myosin II regulates MHC class II trafficking and BCR-driven antigen presentation.
Antigen (Ag) capture and presentation onto major histocompatibility complex (MHC) class II molecules by B lymphocytes is mediated by their surface Ag receptor (B cell receptor [BCR]). Therefore, the transport of vesicles that carry MHC class II and BCR-Ag complexes must be coordinated for them to converge for processing. In this study, we identify the actin-associated motor protein myosin II as being essential for this process. Myosin II is activated upon BCR engagement and associates with MHC class II-invariant chain complexes. Myosin II inhibition or depletion compromises the convergence and concentration of MHC class II and BCR-Ag complexes into lysosomes devoted to Ag processing. Accordingly, the formation of MHC class II-peptides and subsequent CD4 T cell activation are impaired in cells lacking myosin II activity. Therefore, myosin II emerges as a key motor protein in BCR-driven Ag processing and presentation.
Vascotto
Fulvia
F
Institut National de la Santé et de la Recherche Medicale Unité 653, Unité Mixte de Recherche 144 Institut Curie, 75005 Paris, France.
Lankar
Danielle
D
Faure-André
Gabrielle
G
Vargas
Pablo
P
Diaz
Jheimmy
J
Le Roux
Delphine
D
Yuseff
Maria-Isabel
MI
Sibarita
Jean-Baptiste
JB
Boes
Marianne
M
Raposo
Graça
G
Mougneau
Evelyne
E
Glaichenhaus
Nicolas
N
Bonnerot
Christian
C
Manoury
Bénédicte
B
Lennon-Duménil
Ana-Maria
AM
D000199:Actins / Q000378:metabolism; D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D000949:Histocompatibility Antigens Class II / Q000276:immunology / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000276:immunology; D008247:Lysosomes / Q000276:immunology / Q000378:metabolism; D046911:Macromolecular Substances / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D024462:Myosin Type II / Q000276:immunology / Q000378:metabolism*; D021381:Protein Transport / Q000276:immunology; D011947:Receptors, Antigen, B-Cell / Q000276:immunology / Q000378:metabolism*; D022161:Transport Vesicles / Q000276:immunology / Q000378:metabolism*
D000199:Actins; D000949:Histocompatibility Antigens Class II; D046911:Macromolecular Substances; D011947:Receptors, Antigen, B-Cell; D024462:Myosin Type II