Characterization of muscle filamin isoforms suggests a possible role of gamma-filamin/ABP-L in sarcomeric Z-disc formation

Cell Motil Cytoskeleton. 2000 Feb;45(2):149-62. doi: 10.1002/(SICI)1097-0169(200002)45:2<149::AID-CM6>3.0.CO;2-G.


Filamin, also called actin binding protein-280, is a dimeric protein that cross-links actin filaments in the cortical cytoplasm. In addition to this ubiquitously expressed isoform (FLN1), a second isoform (ABP-L/gamma-filamin) was recently identified that is highly expressed in mammalian striated muscles. A monoclonal antibody was developed, that enabled us to identify filamin as a Z-disc protein in mammalian striated muscles by immunocytochemistry and immunoelectron microscopy. In addition, filamin was identified as a component of intercalated discs in mammalian cardiac muscle and of myotendinous junctions in skeletal muscle. Northern and Western blots showed that both, ABP-L/gamma-filamin mRNA and protein, are absent from proliferating cultured human skeletal muscle cells. This muscle specific filamin isoform is, however, up-regulated immediately after the induction of differentiation. In cultured myotubes, ABP-L/gamma-filamin localises in Z-discs already at the first stages of Z-disc formation, suggesting that ABP-L/gamma-filamin might play a role in Z-disc assembly.

MeSH terms

  • 3T3 Cells
  • Amino Acid Sequence
  • Animals
  • Antibodies / immunology
  • Cattle
  • Cell Differentiation
  • Cells, Cultured
  • Contractile Proteins / chemistry
  • Contractile Proteins / metabolism*
  • Contractile Proteins / ultrastructure
  • Filamins
  • Humans
  • Mice
  • Microfilament Proteins / chemistry
  • Microfilament Proteins / metabolism*
  • Microfilament Proteins / ultrastructure
  • Molecular Sequence Data
  • Muscle, Skeletal / cytology
  • Muscle, Skeletal / metabolism*
  • Muscle, Skeletal / ultrastructure
  • Protein Isoforms / metabolism
  • Rats
  • Sarcomeres / chemistry
  • Sarcomeres / metabolism*
  • Sarcomeres / ultrastructure
  • Sequence Homology, Amino Acid


  • Antibodies
  • Contractile Proteins
  • FLNA protein, human
  • FLNC protein, human
  • Filamins
  • Microfilament Proteins
  • Protein Isoforms