Membrane orientation of the precursor 74-kDa form of L-histidine decarboxylase

Inflamm Res. 2006 May;55(5):185-91. doi: 10.1007/s00011-006-0069-x.

Abstract

Objective: We previously demonstrated that, when expressed in COS-7 cells, L-histidine decarboxylase (HDC), which has neither an amino terminal signal sequence nor a hydrophobic membrane anchor, was localized in the endoplasmic reticulum (ER), although its orientation in the membrane remains to be clarified.

Methods & results: Protease digestion and immunofluorescence analyses of the cells, of which plasma membrane was selectively permeabilized, revealed that the amino terminal 50-kDa portion of HDC is hardly accessible to proteases and antibodies added exogenously from the cytosolic side. Green fluorescent protein fused with the carboxyl terminal 20-kDa region of HDC at its carboxyl terminus exhibited the same characteristics as native HDC.

Conclusion: These results indicate that HDC is tightly associated with the ER membrane with its carboxyl terminal region exposed on the cytosolic side.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Proteins / pharmacology
  • COS Cells
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cell Membrane Permeability / drug effects
  • Chlorocebus aethiops
  • Endoplasmic Reticulum / enzymology*
  • Histidine Decarboxylase / chemistry*
  • Histidine Decarboxylase / metabolism
  • Intracellular Membranes / enzymology*
  • L-Lactate Dehydrogenase / metabolism
  • Streptolysins / pharmacology

Substances

  • Bacterial Proteins
  • Streptolysins
  • streptolysin O
  • L-Lactate Dehydrogenase
  • Histidine Decarboxylase