An alpha-actinin binding site of zyxin is essential for subcellular zyxin localization and alpha-actinin recruitment.

The LIM domain protein zyxin is a component of adherens type junctions, stress fibers, and highly dynamic membrane areas and appears to be involved in microfilament organization. Chicken zyxin and its human counterpart display less than 60% sequence identity, raising concern about their functional identity. Here, we demonstrate that human ...
zyxin, like the avian protein, specifically interacts with alpha-actinin. Furthermore, we map the interaction site to a motif of approximately 22 amino acids, present in the N-terminal domain of human zyxin. This motif is both necessary and sufficient for alpha-actinin binding, whereas a downstream region, which is related in sequence, appears to be dispensable. A synthetic peptide comprising human zyxin residues 21-42 specifically binds to alpha-actinin in solid phase binding assays. In contrast to full-length zyxin, constructs lacking this motif do not interact with alpha-actinin in blot overlays and fail to recruit alpha-actinin in living cells. When zyxin lacking the alpha-actinin binding site is expressed as a fusion protein with green fluorescent protein, association of the recombinant protein with stress fibers is abolished, and targeting to focal adhesions is grossly impaired. Our results suggest a crucial role for the alpha-actinin-zyxin interaction in subcellular zyxin localization and microfilament organization.
Mesh Terms:
Actinin, Amino Acid Sequence, Animals, Avian Proteins, Base Sequence, Binding Sites, Chickens, Conserved Sequence, Cytoskeletal Proteins, DNA Primers, Evolution, Glycoproteins, Humans, Metalloproteins, Molecular Sequence Data, Recombinant Fusion Proteins, Sequence Deletion, Sequence Homology, Amino Acid, Subcellular Fractions
J. Biol. Chem.
Date: May. 07, 1999
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