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PROTEIN RETENTION IN THE ENDOPLASMIC RETICULUM OF INSECT CELLS IS NOT COMPROMISED BY BACULOVIRUS INFECTION
Author(s) -
HENDERSON JANEY,
MACDONALD HEATHER,
LAZARUS COLIN M.,
NAPIER RICHARD M.,
HAWES CHRIS R.
Publication year - 1996
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1006/cbir.1996.0052
Subject(s) - kdel , endoplasmic reticulum , er retention , signal peptide , microbiology and biotechnology , biology , secretion , secretory pathway , secretory protein , cell culture , biochemistry , recombinant dna , gene , genetics , mutant , golgi apparatus
High level expression of the major auxin‐binding protein (ABP1) from maize ( Zea mays L.) has been used to demonstrate that the machinery for retaining proteins in the endoplasmic reticulum (ER) of insect cells functions efficiently throughout the baculovirus infection cycle. Immuno‐localization showed wild‐type ABP1 (ABP1‐KDEL) to be targeted to the lumen of the ER, in accordance with its signal peptide and carboxyterminal KDEL ER‐retention signal. The protein accumulated in dilations of the ER, and none was detected at the cell surface. Immunoblotting of concentrated culture medium confirmed that ABP1‐KDEL was not secreted at a detectable level. In contrast, when the carboxyterminus was mutated to KEQL, secretion of the baculovirus‐expressed protein was readily detected. Immunolocalization and immunoblotting demonstrated that a high proportion of the ABP1‐KEQL protein was secreted at the cell surface and into the culture medium. The data demonstrate that the ER of insect cells has a great capacity to retain proteins and that this property is largely unaffected by the cellular disruption caused by baculovirus replication.