Molecular characterization of KEX1, a kexin-like protease in mouse Pneumocystis carinii

Gene. 2000 Jan 25;242(1-2):141-50. doi: 10.1016/s0378-1119(99)00533-8.

Abstract

Expression screening of a Pneumocystis carinii-infected mouse lung cDNA library with specific monoclonal antibodies (mAbs) led to the identification of a P. carinii cDNA with extensive homology to subtilisin-like proteases, particularly fungal kexins and mammalian prohormone convertases. The 3.1 kb cDNA contains a single open reading frame encoding 1011 amino acids. Structural similarities to fungal kexins in the deduced primary amino acid sequence include a putative proenzyme domain delineated by a consensus autocatalytic cleavage site (Arg-Glu-Lys-Arg), conserved Asp, His, Asn and Ser residues in the putative catalytic domain, a hydrophobic transmembrane spanning domain, and a carboxy-terminal cytoplasmic domain with a conserved tyrosine motif thought to be important for localization of the protease in the endoplasmic reticulum and/or Golgi apparatus. Based on these structural similarities and the classification of P. carinii as a fungus, the protease was named KEX1. Southern blotting of mouse P. carinii chromosomes localized kex1 to a single chromosome of approximately 610 kb. Southern blotting of restriction enzyme digests of genomic DNA from P. carinii-infected mouse lung demonstrated that kex1 is a single copy gene. The function of kexins in other fungi suggests that KEX1 may be involved in the post-translational processing and maturation of other P. carinii proteins.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Blotting, Southern
  • Carboxypeptidases / genetics*
  • Chromosomes, Fungal / genetics
  • Cloning, Molecular
  • DNA / genetics
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics
  • DNA, Fungal / genetics
  • Electrophoresis, Gel, Pulsed-Field
  • Lung / metabolism
  • Lung / microbiology
  • Mice
  • Molecular Sequence Data
  • Pneumocystis / genetics*
  • Proprotein Convertases*
  • Saccharomyces cerevisiae Proteins*
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Subtilisins / genetics*

Substances

  • DNA, Complementary
  • DNA, Fungal
  • Saccharomyces cerevisiae Proteins
  • DNA
  • Carboxypeptidases
  • carboxypeptidase D
  • Proprotein Convertases
  • Subtilisins
  • KEX2 protein, S cerevisiae

Associated data

  • GENBANK/AF093132