CD2AP is indispensable to multistep cytotoxic process by NK cells.
CD2-associated protein (CD2AP) is a cytoplasmic protein which localizes to membrane ruffles, lipid rafts and the leading edges of cells. It is implicated in podocyte homeostasis, signal transduction, dynamic actin remodeling and also membrane trafficking during endocytosis and cytokinesis. CD2AP was reported to orchestrate receptor patterning and cytoskeletal polarity in T cell contacts and it could also modulate TCR signaling. However, whether it plays a role in NK cell killing remains unknown. In this study, we discovered that interfering with CD2AP expression strongly reduced cytotoxicity of human NK92 cell line and this effect was independent of FasL sensitivity of target cells. Conjugate formation and degranulation were impeded in NK92 cells after CD2AP knockdown. Upon encountering target cells, CD2AP in NK92 is enriched near contact site and colocalizes with FasL-bearing granules. In contrast, FasL-bearing granules were found rarely polarized toward cell contact site after CD2AP knockdown. Furthermore, by immunoprecipitation from NK92 cell lysates and transient expression studies in 293T and Hela cells, we demonstrated that CD2AP associates with FasL. Thus, CD2AP, through facilitating conjugate formation and directed transport of lytic granules, plays an important role in NK cells killing.
Ma
Yuting
Y
Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Yang
Heng
H
Qi
Jing
J
Liu
Dongfang
D
Xiong
Ping
P
Xu
Yong
Y
Feng
Wei
W
Zheng
Guoying
G
Li
Pan
P
Fang
Min
M
Tan
Zheng
Z
Zheng
Fang
F
Gong
Feili
F
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000276:immunology*; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000276:immunology*; D053222:Fas Ligand Protein / Q000235:genetics / Q000276:immunology*; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D019169:Jurkat Cells; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000276:immunology*; D021962:Membrane Microdomains / Q000235:genetics / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology; D022142:Secretory Vesicles / Q000235:genetics / Q000276:immunology*
D048868:Adaptor Proteins, Signal Transducing; C114545:CD2-associated protein; D003598:Cytoskeletal Proteins; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D011948:Receptors, Antigen, T-Cell