UNC-45A Is a Nonmuscle Myosin IIA Chaperone Required for NK Cell Cytotoxicity via Control of Lytic Granule Secretion.


NK cell's killing is a tightly regulated process under the control of specific cytoskeletal proteins. This includes Wiskott-Aldrich syndrome protein, Wiskott-Aldrich syndrome protein-interacting protein, cofilin, Munc13-4, and nonmuscle myosin IIA (NMIIA). These proteins play a key role in controlling NK-mediated cytotoxicity either via regulating the attachment of lytic granules to the actin-based cytoskeleton or via promoting the cytoskeletal reorganization that is requisite for lytic granule release. UNC-45A is a highly conserved member of the UNC-45/CRO1/She4p family of proteins that act as chaperones for both conventional and nonconventional myosin. Although we and others have shown that in lower organisms and in mammalian cells NMIIA-associated functions, such as cytokinesis, cell motility, and organelle trafficking, are dependent upon the presence of UNC-45A, its role in NK-mediated functions is largely unknown. In this article, we describe UNC-45A as a key regulator of NK-mediated cell toxicity. Specifically we show that, in human NK cells, UNC-45A localize at the NK cell immunological synapse of activated NK cells and is part of the multiprotein complex formed during NK cell activation. Furthermore, we show that UNC-45A is disposable for NK cell immunological synapse formation and lytic granules reorientation but crucial for lytic granule exocytosis. Lastly, loss of UNC-45A leads to reduced NMIIA binding to actin, suggesting that UNC-45A is a crucial component in regulating human NK cell cytoskeletal dynamics via promoting the formation of actomyosin complexes.

DOI: 10.4049/jimmunol.1500979

Cite this paper

@article{Iizuka2015UNC45AIA, title={UNC-45A Is a Nonmuscle Myosin IIA Chaperone Required for NK Cell Cytotoxicity via Control of Lytic Granule Secretion.}, author={Yoshie Iizuka and Frank M Cichocki and Andrew Sieben and Fabio Sforza and Razaul Karim and Kathleen A Coughlin and Rachel Isaksson Vogel and Riccardo Gavioli and Valarie McCullar and Todd R. Lenvik and Michael Lee and Jeffrey Scott Miller and Martina Bazzaro}, journal={Journal of immunology}, year={2015}, volume={195 10}, pages={4760-70} }