Human beta-filamin is a new protein that interacts with the cytoplasmic tail of glycoprotein Ibalpha

J Biol Chem. 1998 Jul 10;273(28):17531-8. doi: 10.1074/jbc.273.28.17531.


We have cloned and sequenced a 9.4-kilobase cDNA specifying a new 280-kDa protein interacting with the cytoplasmic tail of glycoprotein (Gp) Ibalpha and showing considerable homology to actin-binding protein 280 (ABP-280) and chicken retinal filamin. We term this protein human beta-filamin. The gene for beta-filamin localizes to chromosome 3p14.3-p21.1. beta-Filamin mRNA expression was observed in many tissues and in cultured human umbilical vein endothelial cells (HUVECs); only minimal expression was detected in platelets and the megakaryocytic cell line CHRF-288. Like ABP-280, beta-filamin contains an NH2-terminal actin-binding domain, a backbone of 24 tandem repeats, and two "hinge" regions. A polyclonal antibody to the unique beta-filamin first hinge sequence identifies a strong 280-kDa band in HUVECs but only a weak band in platelets, and stains normal human endothelial cells in culture and in situ. We have confirmed the interaction of beta-filamin and GpIbalpha in platelet and HUVEC lysates. In addition, using two-hybrid analysis with deletion mutants, we have localized the binding domain for GpIbalpha in beta-filamin to residues 1862-2148, an area homologous to the GpIbalpha binding domain in ABP-280. beta-Filamin is a new member of the filamin family that may have significance for GpIbalpha function in endothelial cells and platelets.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Carrier Proteins / chemistry
  • Carrier Proteins / genetics
  • Chromosome Mapping
  • Chromosomes, Human, Pair 3
  • Contractile Proteins / chemistry
  • Contractile Proteins / genetics
  • Cytoplasm / metabolism*
  • DNA, Complementary
  • Filamins
  • Humans
  • Immunohistochemistry
  • Microfilament Proteins / chemistry
  • Microfilament Proteins / genetics
  • Microfilament Proteins / metabolism*
  • Molecular Sequence Data
  • Platelet Glycoprotein GPIb-IX Complex / metabolism*
  • Protein Binding
  • RNA, Messenger / genetics
  • Sequence Homology, Amino Acid


  • Carrier Proteins
  • Contractile Proteins
  • DNA, Complementary
  • FLNC protein, human
  • Filamins
  • Microfilament Proteins
  • Platelet Glycoprotein GPIb-IX Complex
  • RNA, Messenger

Associated data

  • GENBANK/AF042166