Zyxin interacts with the SH3 domains of the cytoskeletal proteins LIM-nebulette and Lasp-1.
Zyxin is a versatile component of focal adhesions in eukaryotic cells. Here we describe a novel binding partner of zyxin, which we have named LIM-nebulette. LIM-nebulette is an alternative splice variant of the sarcomeric protein nebulette, which, in contrast to nebulette, is expressed in non-muscle cells. It displays a modular structure with an N-terminal LIM domain, three nebulin-like repeats, and a C-terminal SH3 domain and shows high similarity to another cytoskeletal protein, Lasp-1 (LIM and SH3 protein-1). Co-precipitation studies and results obtained with the two-hybrid system demonstrate that LIM-nebulette and Lasp-1 interact specifically with zyxin. Moreover, the SH3 domain from LIM-nebulette is both necessary and sufficient for zyxin binding. The SH3 domains from Lasp-1 and nebulin can also interact with zyxin, but the SH3 domains from more distantly related proteins such as vinexin and sorting nexin 9 do not. On the other hand, the binding site in zyxin is situated at the extreme N terminus as shown by site-directed mutagenesis. LIM-nebulette and Lasp-1 use the same linear binding motif. This motif shows some similarity to a class II binding site but does not contain the classical PXXP sequence. LIM-nebulette reveals a subcellular distribution at focal adhesions similar to Lasp-1. Thus, LIM-nebulette, Lasp-1, and zyxin may play an important role in the organization of focal adhesions.
ITI Research Institute, University of Bern, P. O. Box 54, CH-3010 Bern, Switzerland.
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Zhuang
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D048868:Adaptor Proteins, Signal Transducing; D017398:Alternative Splicing; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D005091:Exons; D022001:Focal Adhesions / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D060588:LIM Domain Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000737:chemistry / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D009363:Neoplasm Proteins; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D058305:Sorting Nexins; D014018:Tissue Distribution; D014162:Transfection; D020798:Two-Hybrid System Techniques; D033921:Vesicular Transport Proteins; D060589:Zyxin; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; D006023:Glycoproteins; D018398:Homeodomain Proteins; C096353:LASP1 protein, human; D060588:LIM Domain Proteins; C490692:Lasp1 protein, mouse; D008164:Luminescent Proteins; D009124:Muscle Proteins; C486890:NEBL protein, human; C486891:Nebl protein, mouse; D009363:Neoplasm Proteins; C400533:SNX9 protein, human; C486523:SORBS3 protein, human; C117452:Sorbs3 protein, mouse; D058305:Sorting Nexins; D033921:Vesicular Transport Proteins; C092842:ZYX protein, human; D060589:Zyxin; D049452:Green Fluorescent Proteins; D005982:Glutathione Transferase