| Autor: |
Dudiki T; Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA., Mahajan G; Chemical and Biomedical Engineering Department, Washkewicz College of Engineering, Cleveland State University, Cleveland, OH, 44115, USA., Liu H; Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA., Zhevlakova I; Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA., Bertagnolli C; Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA., Nascimento DW; Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA., Kothapalli CR; Chemical and Biomedical Engineering Department, Washkewicz College of Engineering, Cleveland State University, Cleveland, OH, 44115, USA. c.kothapalli@csuohio.edu., Byzova TV; Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA. byzovat@ccf.org. |
| Abstrakt: |
Kindlin3 (K3), a FERM domain containing protein expressed in hematopoietic cells controls integrin activation and thus hemostatic and inflammatory responses. However, its role in the mechanics of plasma membrane remains unclear. Here, we show that genetic knockout of K3 in microglia and macrophages resulted in defective plasma membrane tension and membrane blebbing. Atomic force microscopy (AFM) of K3-deficient cells revealed a significant loss in membrane-to-cortex attachment (MCA), and consequently reduced membrane tension. This loss in MCA is amplified by the mislocalization of the cell cortex proteins-ezrin, radixin, and moesin (ERM)-to the plasma membrane of microglia and macrophages. Re-expression of K3 in K3-deficient macrophages rescued the defects and localization of ERMs implying a key role for K3 in MCA. Analysis of two K3 mutants, K3 int affecting integrin binding and activation, and K3 pxn/act disrupting binding to paxillin and actin but not integrin functions, demonstrated that the role of K3 in membrane mechanics is separate from integrin activation. The K3 pxn/act mutant substantially diminished both membrane tension and Yes-associated protein (YAP) translocation to the nucleus, while preserving integrin activation, cell spreading, and migration. Together, our results show that K3 coordinates membrane mechanics, ERM protein recruitment to the membrane, and YAP translocation by linking integrin at the membrane to paxillin and actin of the cytoskeleton. This novel function of K3 is distinct from its role in integrin activation. |
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