Membrane targeting and binding of the 74-kDa form of mouse l-histidine decarboxylase via its carboxyl-terminal sequence

Abstract

The role of the C-terminal region of the 74-kDa form of l-histidine decarboxylase (HDC) in the targeting to the endoplasmic reticulum (ER) was investigated in COS-7 cells. The deletion of a 10-kDa segment (residues 578–662) of the C-terminal end of HDC, especially a 20 amino acid sequence (residues 588–607), abrogated the targeting to the ER. The C-terminal 10-kDa portion is sufficient to target the green fluorescent protein (GFP) to the ER. The 74-kDa form of HDC synthesized in an in vitro translation system post-translationally associated with the heterogeneous canine microsomal membranes. These results suggest that the C-terminal 10-kDa portion of HDC contains a signal necessary for HDC to be targeted to the ER membrane.