Molecular Dissection of Zyxin Function Reveals Its Involvement in Cell Motility

Abstract

Spatially controlled actin filament assembly is critical for numerous processes, including the vectorial cell migration required for wound healing, cell- mediated immunity, and embryogenesis. One protein implicated in the regulation of actin assembly is zyxin, a protein concentrated at sites where the fast growing ends of actin filaments are enriched. To evaluate the role of zyxin in vivo, we developed a specific peptide inhibitor of zyxin function that blocks its interaction with α-actinin and displaces it from its normal subcellular location. Mislocalization of zyxin perturbs cell migration and spreading, and affects the behavior of the cell edge, a structure maintained by assembly of actin at sites proximal to the plasma membrane. These results support a role for zyxin in cell motility, and demonstrate that the correct positioning of zyxin within the cell is critical for its physiological function. Interestingly, the mislocalization of zyxin in the peptide-injected cells is accompanied by disturbances in the distribution of Ena/VASP family members, proteins that have a well-established role in promoting actin assembly. In concert with previous work, our findings suggest that zyxin promotes the spatially restricted assembly of protein complexes necessary for cell motility.

Overexpression of LASP-1 mediates migration and proliferation of human ovarian cancer cells and influences zyxin localisation

“…This is in agreement with previous findings using a nongenetic approach and injecting a peptide derived from the N-terminus of zyxin to displace zyxin from its normal subcellular location thus leading to reduced cell migration (Drees et al, 1999). On the other hand, the knock-down of zyxin in SKOV-3 cells had no influence on cell migration while genetically zyxin-deficient fibroblasts display enhanced migration (Hoffman et al, 2006).…”

Novel identification of zyxin upregulations in the motile phenotype of hepatocellular carcinoma

“…17 We also examined the role of ZYX in hepatocellular carcinoma cell invasion and migration, since ZYX has a reported role in mediating cell motility in vitro. 18 Following ZYX expression knockdown, the ability of hepatocellular carcinoma cells to pass through the extracellular matrix and to migrate towards the chemo-attractant fetal bovine serum were both attenuated. These results suggest that ZYX expression plays a role in hepatocellular carcinoma cell motility and potentially underlined its function in tumor cell dissemination.…”

α‐actinin revisited: A fresh look at an old player

“…The LIM domain, which has the structure of a double zinc finger, is common to many proteins that regulate cell differentiation, and multiple copies of the LIM domain are found in the cytoskeletal proteins zyxin, the cysteine-rich protein (CRP), and other members of the CRP family [reviewed in Beckerle, 1997]. Zyxin appears to function as a scaffold for the assembly of protein complexes involved in regulating cell motility and differentiation, and it cycles between the nucleus and the cytoskeleton [Drees et al, 1999;Nix et al, 2001]. Zyxin binds to the smaller LIM domain protein CRP, and ␣-actinin binds directly to both zyxin and CRP, suggesting that ␣-actinin itself may serve a scaffolding function by regulating interactions and subcellular distribution of these two proteins [Crawford et al, 1992;Pomies et al, 1997;Reinhard et al, 1999].…”