TY - JOUR
T1 - Interplay between membrane elasticity and active cytoskeleton forces regulates the aggregation dynamics of the immunological synapse
AU - Dharan, Nadiv
AU - Farago, Oded
N1 - Funding Information:
This work was supported by the Israel Science Foundation (ISF) through grant 1087/13.
Publisher Copyright:
© 2017 The Royal Society of Chemistry.
PY - 2017/1/1
Y1 - 2017/1/1
N2 - Adhesion between a T cell and an antigen presenting cell is achieved by TCR-pMHC and LFA1-ICAM1 protein complexes. These segregate to form a special pattern, known as the immunological synapse (IS), consisting of a central quasi-circular domain of TCR-pMHC bonds surrounded by a peripheral domain of LFA1-ICAM1 complexes. Insights gained from imaging studies had led to the conclusion that the formation of the central adhesion domain in the IS is driven by active (ATP-driven) mechanisms. Recent studies, however, suggested that passive (thermodynamic) mechanisms may also play an important role in this process. Here, we present a simple physical model, taking into account the membrane-mediated thermodynamic attraction between the TCR-pMHC bonds and the effective forces that they experience due to ATP-driven actin retrograde flow and transport by dynein motor proteins. Monte Carlo simulations of the model exhibit a good spatio-temporal agreement with the experimentally observed pattern evolution of the TCR-pMHC microclusters. The agreement is lost when one of the aggregation mechanisms is "muted", which helps to identify their respective roles in the process. We conclude that actin retrograde flow drives the centripetal motion of TCR-pMHC bonds, while the membrane-mediated interactions facilitate microcluster formation and growth. In the absence of dynein motors, the system evolves into a ring-shaped pattern, which highlights the role of dynein motors in the formation of the final concentric pattern. The interplay between the passive and active mechanisms regulates the rate of the accumulation process, which in the absence of one them proceeds either too quickly or slowly.
AB - Adhesion between a T cell and an antigen presenting cell is achieved by TCR-pMHC and LFA1-ICAM1 protein complexes. These segregate to form a special pattern, known as the immunological synapse (IS), consisting of a central quasi-circular domain of TCR-pMHC bonds surrounded by a peripheral domain of LFA1-ICAM1 complexes. Insights gained from imaging studies had led to the conclusion that the formation of the central adhesion domain in the IS is driven by active (ATP-driven) mechanisms. Recent studies, however, suggested that passive (thermodynamic) mechanisms may also play an important role in this process. Here, we present a simple physical model, taking into account the membrane-mediated thermodynamic attraction between the TCR-pMHC bonds and the effective forces that they experience due to ATP-driven actin retrograde flow and transport by dynein motor proteins. Monte Carlo simulations of the model exhibit a good spatio-temporal agreement with the experimentally observed pattern evolution of the TCR-pMHC microclusters. The agreement is lost when one of the aggregation mechanisms is "muted", which helps to identify their respective roles in the process. We conclude that actin retrograde flow drives the centripetal motion of TCR-pMHC bonds, while the membrane-mediated interactions facilitate microcluster formation and growth. In the absence of dynein motors, the system evolves into a ring-shaped pattern, which highlights the role of dynein motors in the formation of the final concentric pattern. The interplay between the passive and active mechanisms regulates the rate of the accumulation process, which in the absence of one them proceeds either too quickly or slowly.
UR - http://www.scopus.com/inward/record.url?scp=85030786009&partnerID=8YFLogxK
U2 - 10.1039/c7sm01064h
DO - 10.1039/c7sm01064h
M3 - Article
C2 - 28825081
AN - SCOPUS:85030786009
SN - 1744-683X
VL - 13
SP - 6938
EP - 6946
JO - Soft Matter
JF - Soft Matter
IS - 38
ER -