Expression, subcellular localization, and cloning of the 130-kDa regulatory subunit of myosin phosphatase in porcine aortic endothelial cells

Biochem Biophys Res Commun. 1999 Jan 19;254(2):490-6. doi: 10.1006/bbrc.1998.9973.


In endothelial cells in situ and in primary culture, immunoblot analysis revealed an expression of the 130-kDa subunit of myosin phosphatase, similar to the myosin phosphatase targeting subunit (MYPT) of smooth muscle. Screening of an endothelial cell cDNA library yielded a clone encoding an NH2-terminal fragment of 89.6 kDa, closely related to smooth muscle MYPT1. Two isoforms differing by a central insert of 56 residues were detected. In growing cells, MYPT1 was localized on stress fiber, but at confluence the localization pattern changed and MYPT1 was distributed close to the cell membrane and at cell-cell contacts. The membrane localization of MYPT1 suggested a target other than myosin and raised the possibility that MYPT1 may be involved in dephosphorylation of alternative substrate(s). These distinct mechanisms would also be dependent on the growth state of the endothelial cells, i.e., regulation of actin-myosin interactions in growing cells and an unknown function in cells at confluence.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Aorta, Thoracic
  • Base Sequence
  • Cell Division
  • Cells, Cultured
  • Cloning, Molecular
  • DNA / biosynthesis
  • DNA, Complementary
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / enzymology*
  • Gene Library
  • Immunoblotting
  • Macromolecular Substances
  • Molecular Sequence Data
  • Molecular Weight
  • Myosin-Light-Chain Phosphatase
  • Phosphoprotein Phosphatases / analysis
  • Phosphoprotein Phosphatases / genetics
  • Phosphoprotein Phosphatases / metabolism*
  • Recombinant Proteins / analysis
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Swine


  • DNA, Complementary
  • Macromolecular Substances
  • Recombinant Proteins
  • DNA
  • Phosphoprotein Phosphatases
  • Myosin-Light-Chain Phosphatase

Associated data

  • GENBANK/AB019559