Premium
Comparative efficiencies of C‐terminal signals of native glycophosphatidylinositol (GPI)‐anchored proproteins in conferring GPI‐anchoring
Author(s) -
Chen Rui,
Knez Jansen J.,
Merrick William C.,
Medof M. Edward
Publication year - 2001
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.1267
Subject(s) - anchoring , terminal (telecommunication) , chemistry , microbiology and biotechnology , biology , computer science , psychology , social psychology , telecommunications
Every protein fated to receive the glycophosphatidylinositol (GPI) anchor post‐translational modification has a C‐terminal GPI‐anchor attachment signal sequence. This signal peptide varies with respect to length, content, and hydrophobicity. With the exception of predictions based on an upstream amino acid triplet termed ω→ω + 2 which designates the site of GPI uptake, there is no information on how the efficiencies of different native signal sequences compare in the transamidation reaction that catalyzes the substitution of the GPI anchor for the C‐terminal peptide. In this study we utilized the placental alkaline phosphatase (PLAP) minigene, miniPLAP, and replaced its native 3′ end‐sequence encoding ω‐2 to the C‐terminus with the corresponding C‐terminal sequences of nine other human GPI‐anchored proteins. The resulting chimeras then were fed into an in vitro processing microsomal system where the cleavages leading to mature product from the nascent preproprotein could be followed by resolution on an SDS–PAGE system after immunoprecipitation. The results showed that the native signal of each protein differed markedly with respect to transamidation efficiency, with the signals of three proteins out‐performing the others in GPI‐anchor addition and those of two proteins being poorer substrates for the GPI transamidase. The data additionally indicated that the hierarchical order of efficiency of transamidation did not depend solely on the combination of permissible residues at ω→ω + 2. J. Cell. Biochem. 84: 68–83, 2002. © 2001 Wiley‐Liss, Inc.