B cells extract antigens at arp2/3-generated actin foci interspersed with linear filaments

TY - JOUR

T1 - B cells extract antigens at arp2/3-generated actin foci interspersed with linear filaments

AU - Roper, Sophie I.

AU - Wasim, Laabiah

AU - Malinova, Dessislava

AU - Way, Michael

AU - Cox, Susan

AU - Tolar, Pavel

PY - 2019/12/1

Y1 - 2019/12/1

N2 - Antibody production depends on B cell internalization and presentation of antigens to helper T cells. To acquire antigens displayed by antigen-presenting cells, B cells form immune synapses and extract antigens by the mechanical activity of the acto-myosin cytoskeleton. While cytoskeleton organization driving the initial formation of the B cell synapse has been studied, how the cytoskeleton supports antigen extraction remains poorly understood. Here we show that after initial cell spreading, F-actin in synapses of primary mouse B cells and human B cell lines forms a highly dynamic pattern composed of actin foci interspersed with linear filaments and myosin IIa. The foci are generated by Arp2/3-mediated branched-actin polymerization and stochastically associate with antigen clusters to mediate internalization. However, antigen extraction also requires the activity of formins, which reside near the foci and produce the interspersed filaments. Thus, a cooperation of branched-actin foci supported by linear filaments underlies B cell mechanics during antigen extraction.

AB - Antibody production depends on B cell internalization and presentation of antigens to helper T cells. To acquire antigens displayed by antigen-presenting cells, B cells form immune synapses and extract antigens by the mechanical activity of the acto-myosin cytoskeleton. While cytoskeleton organization driving the initial formation of the B cell synapse has been studied, how the cytoskeleton supports antigen extraction remains poorly understood. Here we show that after initial cell spreading, F-actin in synapses of primary mouse B cells and human B cell lines forms a highly dynamic pattern composed of actin foci interspersed with linear filaments and myosin IIa. The foci are generated by Arp2/3-mediated branched-actin polymerization and stochastically associate with antigen clusters to mediate internalization. However, antigen extraction also requires the activity of formins, which reside near the foci and produce the interspersed filaments. Thus, a cooperation of branched-actin foci supported by linear filaments underlies B cell mechanics during antigen extraction.

UR - http://www.scopus.com/inward/record.url?scp=85076871480&partnerID=8YFLogxK

U2 - 10.7554/eLife.48093

DO - 10.7554/eLife.48093

M3 - Article

C2 - 31815664

AN - SCOPUS:85076871480

SN - 2050-084X

VL - 8

JO - eLife

JF - eLife

M1 - e48093

ER -