- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- Interactions between the extracellular and transmembrane...
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
Interactions between the extracellular and transmembrane domains of IG-alpha/beta heterodimer are required for BCR assembly and cell surface expression Dylke, Janis
Abstract
The B cell antigen receptor (BCR) is expressed on the surface of B-lymphocytes where it binds antigen and transmits signals that regulate B cell activation, growth and differentiation. The BCR is composed of membrane IgM (mlgM) and two signaling proteins, Ig-α and Ig-β. If either of the signaling proteins is not expressed, the incomplete mlgM-containing BCR will not traffic to the cell surface. Our hypothesis is that specific protein:protein interactions between both the extracellular and transmembrane (TM) regions of Ig-α and Ig-β are necessary for receptor assembly, cell surface expression and effective signaling to support the proper development of B cells. While previous work has shown the importance of the T M region in BCR assembly, this study indicates that a heterodimer of the extracellular domains of Ig-α and Ig-β are also required for proper association with mlgM. Cell lines expressing mutated Ig-α proteins that did not heterodimerize with Ig-β in the extracellular and T M domains were unable to properly assemble the BCR. Conversely, an Ig-α mutant with an Ig-β cytoplasmic tail (Cβ (α/α/β)) was able to assemble with the rest of the BCR and traffic to the cell surface. Thus, both the extracellular and TM regions if the Ig-α/Ig-β must be properly associated in order for the BCR to assemble. Additionally, an Ig-α mutant with a truncated cytoplasmic domain (ΔαKVK (α/α/0)) was not able to associate with Ig-β, indicating that the cytoplasmic domain may play a role in BCR assembly. Further studies with truncation mutants are required to confirm this result. In the future additional Ig-α/Ig-β mutants will be expressed to better define the regions of protein:protein interactions.
Item Metadata
Title |
Interactions between the extracellular and transmembrane domains of IG-alpha/beta heterodimer are required for BCR assembly and cell surface expression
|
Creator | |
Publisher |
University of British Columbia
|
Date Issued |
2006
|
Description |
The B cell antigen receptor (BCR) is expressed on the surface of B-lymphocytes where it binds
antigen and transmits signals that regulate B cell activation, growth and differentiation. The
BCR is composed of membrane IgM (mlgM) and two signaling proteins, Ig-α and Ig-β. If either
of the signaling proteins is not expressed, the incomplete mlgM-containing BCR will not traffic
to the cell surface. Our hypothesis is that specific protein:protein interactions between both the
extracellular and transmembrane (TM) regions of Ig-α and Ig-β are necessary for receptor
assembly, cell surface expression and effective signaling to support the proper development of B
cells. While previous work has shown the importance of the T M region in BCR assembly, this
study indicates that a heterodimer of the extracellular domains of Ig-α and Ig-β are also required
for proper association with mlgM. Cell lines expressing mutated Ig-α proteins that did not
heterodimerize with Ig-β in the extracellular and T M domains were unable to properly assemble
the BCR. Conversely, an Ig-α mutant with an Ig-β cytoplasmic tail (Cβ (α/α/β)) was able to
assemble with the rest of the BCR and traffic to the cell surface. Thus, both the extracellular and
TM regions if the Ig-α/Ig-β must be properly associated in order for the BCR to assemble.
Additionally, an Ig-α mutant with a truncated cytoplasmic domain (ΔαKVK (α/α/0)) was not
able to associate with Ig-β, indicating that the cytoplasmic domain may play a role in BCR
assembly. Further studies with truncation mutants are required to confirm this result. In the
future additional Ig-α/Ig-β mutants will be expressed to better define the regions of
protein:protein interactions.
|
Genre | |
Type | |
Language |
eng
|
Date Available |
2010-01-05
|
Provider |
Vancouver : University of British Columbia Library
|
Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
|
DOI |
10.14288/1.0092462
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Graduation Date |
2006-05
|
Campus | |
Scholarly Level |
Graduate
|
Aggregated Source Repository |
DSpace
|
Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.