Molecular cloning and characterization of mouse cardiac junctate isoforms

Biochem Biophys Res Commun. 2001 Dec 14;289(4):882-7. doi: 10.1006/bbrc.2001.6056.


Junctate is a newly identified integral ER/SR membrane calcium binding protein, which is an alternative splicing form of the same gene generating aspartyl beta-hydroxylase and junctin. Screening a mouse heart cDNA library using canine junctin cDNA as a probe yielded three complete mouse heart cDNAs. One of the cDNAs is homologous to the previously reported human junctate. The three mouse junctate proteins are composed of 270, 259, and 215 amino acids (we named them junctate-1, -2, and -3). The apparent molecular masses of the mouse junctates in SDS-PAGE were in the range between 40 and 53 kDa. Northern and Western blot analyses indicate that mouse junctates are expressed in heart, brain, spleen, lung, liver, kidney, and stomach, but not in skeletal muscle. The apparent molecular weights of junctates from heart and brain were somewhat different from those from the other tissues tested, suggesting that there are tissue-specific expression patterns of the different junctate isoforms. Immunohistochemical studies showed that junctates were expressed both in ventricular and atrial tissues. This is the first study that shows the presence of 3 distinct cardiac junctate isoforms expressed in various mammalian tissues.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Calcium-Binding Proteins / chemistry*
  • Calcium-Binding Proteins / genetics*
  • Calcium-Binding Proteins / metabolism
  • Cloning, Molecular
  • DNA, Complementary / genetics
  • Dogs
  • Gene Expression
  • Humans
  • Immunohistochemistry
  • Male
  • Membrane Proteins / chemistry*
  • Membrane Proteins / genetics*
  • Membrane Proteins / metabolism
  • Mice
  • Mixed Function Oxygenases*
  • Molecular Sequence Data
  • Molecular Weight
  • Muscle Proteins*
  • Myocardium / metabolism*
  • Protein Isoforms / chemistry
  • Protein Isoforms / genetics
  • Sequence Homology, Amino Acid
  • Tissue Distribution


  • Calcium-Binding Proteins
  • DNA, Complementary
  • Membrane Proteins
  • Muscle Proteins
  • Protein Isoforms
  • Asph protein, mouse
  • Mixed Function Oxygenases
  • ASPH protein, human

Associated data

  • GENBANK/AF302653
  • GENBANK/AF302654
  • GENBANK/AF302655