Apolipoprotein B (ApoB) is the only protein component of the low density lipoproteins (LDL) in plasma. It is a glycoprotein with a molecular mass of about 550 kDa (4536 amino acids) containing 16 N-glycans. We have studied the interaction of ApoB with two lectin-like chaperones of the Endoplasmic Reticulum (ER)’Calnexin (CN) and Calreticulin (CR). Using a co-immunoprecipitation approach we observed that newly synthesized ApoB associates with CN and CR. The interaction was transient; within 30–60 min after synthesis bulk of newly formed ApoB dissociated. Using McA Rh7777 cells expressing an N-terminal fragment of ApoB we found that inhibition of glucosidases in the ER prevented the association of CN and CR to newly synthesized ApoB. The results showed that like for association with other glycoprotein substrates, trimming of glucose residues was essential for ApoB binding to CN and CR.
Skip Nav Destination
Article navigation
Research Article|
June 01 1999
Interaction of Newly Synthesized Apolipoprotein B with Calnexin and Calreticulin Requires Glucose Trimming in the Endoplasmic Reticulum
Utpal Tatu;
Utpal Tatu
1Department of Biochemistry, Indian Institute of Science, Bangalore, 560 012, India
Search for other works by this author on:
Ari Helenius
Ari Helenius
2Institute of Biochemistry, Universitaetstr. 16, ETH-Zurich, CH-8092, Switzerland
Search for other works by this author on:
Publisher: Portland Press Ltd
Online ISSN: 1573-4935
Print ISSN: 0144-8463
© 1999 Plenum Publishing Corporation
1999
Biosci Rep (1999) 19 (3): 189–196.
Citation
Utpal Tatu, Ari Helenius; Interaction of Newly Synthesized Apolipoprotein B with Calnexin and Calreticulin Requires Glucose Trimming in the Endoplasmic Reticulum. Biosci Rep 1 June 1999; 19 (3): 189–196. doi: https://doi.org/10.1023/A:1020225803282
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Captcha Validation Error. Please try again.