MEMBRANE TARGETING AND BINDING OF THE 74-KDA FORM OF MOUSE L-HISTIDINE DECARBOXYLASE VIA ITS CARBOXYL-TERMINAL SEQUENCE

The role of the C-terminal region of the 74-kDa form of L-histidine de carboxylase (HDC) in the targeting to the endoplasmic reticulum (ER) w as investigated in COS-7 cells. The deletion of a 10-kDa segment (resi dues 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 IO-M)a 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 posttranslationally associated with the heter ogeneous 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. (C) 1998 Federation of European Bioch emical Societies.