Ser/Thr-rich Repetitive Motifs as Targets for Phosphoglycan Modifications in Leishmania Mexicana Secreted Acid Phosphatase

EMBO J. 1995 Mar 15;14(6):1067-74.


The insect stage of the protozoan parasite Leishmania mexicana secretes a phosphomonoesterase in the form of a filamentous complex. The polypeptide subunits of this polymer are modified by phosphoglycans and/or oligomannosyl residues linked to phosphoserine. Based on peptide sequence data of a predominant 100 kDa protein of the filamentous complex, two tandemly arranged, single copy genes, lmsap1 and lmsap2, were cloned and sequenced. lmsap1 predicts a protein with features characteristic of acid phosphatases and a remarkable serine- and threonine-rich region of 32 amino acids close to the C-terminus. In the otherwise identical lmsap2 product, this region is extended to 383 amino acids and is composed of short Ser/Thr-rich repeats. Deletion analysis demonstrates that lmsap1 encodes the major 100 kDa protein of the complex while a minor 200 kDa component is derived from the lmsap2 gene. Null mutants of either gene retain the ability to secrete acid phosphatase filaments, while a deletion of both genes results in Leishmania defective in enzyme formation. The Ser/Thr-rich domains are the targets for phosphoglycan modifications as shown by the expression of secreted fusion proteins composed of these C-terminal regions and the N-terminal domain of a lysosomal acid phosphatase.

MeSH terms

  • Acid Phosphatase / analysis
  • Acid Phosphatase / chemistry
  • Acid Phosphatase / genetics*
  • Acid Phosphatase / isolation & purification
  • Acid Phosphatase / metabolism
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Carbohydrate Sequence
  • Cloning, Molecular
  • DNA, Protozoan / analysis
  • Genes, Protozoan / genetics*
  • Leishmania mexicana / enzymology*
  • Leishmania mexicana / genetics
  • Lysosomes / enzymology
  • Molecular Sequence Data
  • Oligosaccharides / metabolism
  • Protozoan Proteins*
  • RNA, Messenger / analysis
  • RNA, Protozoan / analysis
  • Recombinant Fusion Proteins / analysis
  • Recombinant Fusion Proteins / metabolism
  • Repetitive Sequences, Nucleic Acid / genetics*
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Sequence Deletion / physiology
  • Serine / metabolism
  • Threonine / metabolism


  • DNA, Protozoan
  • Oligosaccharides
  • Protozoan Proteins
  • RNA, Messenger
  • RNA, Protozoan
  • Recombinant Fusion Proteins
  • Threonine
  • Serine
  • Acid Phosphatase
  • Lmsap1 protein, Leishmania mexicana

Associated data

  • GENBANK/Z46969
  • GENBANK/Z46970
  • GENBANK/Z46971