Lasp-2 expression, localization, and ligand interactions: a new Z-disc scaffolding protein.
The nebulin family of actin-binding proteins plays an important role in actin filament dynamics in a variety of cells including striated muscle. We report here the identification of a new striated muscle Z-disc associated protein: lasp-2 (LIM and SH3 domain protein-2). Lasp-2 is the most recently identified member of the nebulin family. To evaluate the role of lasp-2 in striated muscle, lasp-2 gene expression and localization were studied in chick and mouse tissue, as well as in primary cultures of chick cardiac and skeletal myocytes. Lasp-2 mRNA was detected as early as chick embryonic stage 25 and lasp-2 protein was associated with developing premyofibril structures, Z-discs of mature myofibrils, focal adhesions, and intercalated discs of cultured cardiomyocytes. Expression of GFP-tagged lasp-2 deletion constructs showed that the C-terminal region of lasp-2 is important for its localization in striated muscle cells. Lasp-2 organizes actin filaments into bundles and interacts directly with the Z-disc protein alpha-actinin. These results are consistent with a function of lasp-2 as a scaffolding and actin filament organizing protein within striated muscle Z-discs.
Zieseniss
Anke
A
Department of Cell Biology and Anatomy, University of Arizona, Tucson, Arizona 85724, USA.
Terasaki
Asako G
AG
Gregorio
Carol C
CC
D000185:Actinin / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D003598:Cytoskeletal Proteins / Q000096:biosynthesis* / Q000235:genetics; D060588:LIM Domain Proteins; D008024:Ligands; D051379:Mice; D009124:Muscle Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D054792:Muscle, Striated / Q000737:chemistry / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000737:chemistry / Q000378:metabolism; D009210:Myofibrils / Q000378:metabolism; D012518:Sarcomeres / Q000737:chemistry / Q000378:metabolism*
D000199:Actins; D003598:Cytoskeletal Proteins; D060588:LIM Domain Proteins; D008024:Ligands; D009124:Muscle Proteins; C486891:Nebl protein, mouse; D000185:Actinin