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Besides an ITIM/SHP-1-dependent pathway, CD22 collaborates with Grb2 and plasma membrane calcium-ATPase in an ITIM/SHP-1-independent pathway of attenuation of Ca2+i signal in B cells
- Source :
- Oncotarget
- Publication Year :
- 2016
- Publisher :
- Impact Journals LLC, 2016.
-
Abstract
- CD22 is a surface immunoglobulin implicated in negative regulation of B cell receptor (BCR) signaling; particularly inhibiting intracellular Ca2+ (Ca2+i)signals. Its cytoplasmic tail contains six tyrosine residues (Y773/Y783/Y817/Y828/Y843/Y863, designated Y1~Y6 respectively), including three (Y2/5/6) lying within immunoreceptor tyrosine-based inhibitory motifs (ITIMs) that serve to recruit the protein tyrosine phosphatase SHP-1 after BCR activation-induced phosphorylation. The mechanism of inhibiting Ca2+i by CD22 has been poorly understood. Previous study demonstrated that CD22 associated with plasma membrane calcium-ATPase (PMCA) and enhanced its activity (Chen, J. et al. Nat Immunol 2004;5:651-7). The association is dependent on BCR activation-induced cytoplasmic tyrosine phosphorylation, because CD22 with either all six tyrosines mutated to phenylalanines or cytoplasmic tail truncated loses its ability to associate with PMCA. However, which individual or a group of tyrosine residues determine the association and how CD22 and PMCA interacts, are still unclear. In this study, by using a series of CD22 tyrosine mutants, we found that ITIM Y2/5/6 accounts for 34.3~37.1% Ca2+i inhibition but is irrelevant for CD22/PMCA association. Non-ITIM Y4 and its YEND motif contribute to the remaining 69.4~71.7% Ca2+i inhibition and is the binding site for PMCA-associated Grb2. Grb2, independently of BCR cross-linking, is constitutively associated with and directly binds to PMCA in both chicken and human B cells. Knockout of Grb2 by CRISPR/Cas9 completely disrupted the CD22/PMCA association. Thus, our results demonstrate for the first time that in addition to previously-identified ITIM/SHP-1-dependent pathway, CD22 holds a major pathway of negative regulation of Ca2+i signal, which is ITIM/SHP-1-independent, but Y4/Grb2/PMCA-dependent.
- Subjects :
- 0301 basic medicine
Male
Sialic Acid Binding Ig-like Lectin 2
Protein Tyrosine Phosphatase, Non-Receptor Type 11
Protein tyrosine phosphatase
protein-protein interaction
chemistry.chemical_compound
Gene Knockout Techniques
0302 clinical medicine
hemic and lymphatic diseases
Medicine
Tyrosine
Phosphorylation
RNA, Small Interfering
B cells activation
B-Lymphocytes
biology
Protein Tyrosine Phosphatase, Non-Receptor Type 6
Middle Aged
Healthy Volunteers
Cell biology
Oncology
Female
RNA Interference
GRB2
Signal transduction
Research Paper
Signal Transduction
Adult
B-cell receptor
Receptors, Antigen, B-Cell
calcium signaling
03 medical and health sciences
Plasma Membrane Calcium-Transporting ATPases
plasma membrane calcium-transporting ATPase 4b
Cell Line, Tumor
Animals
Humans
Point Mutation
Protein Interaction Domains and Motifs
GRB2 Adaptor Protein
business.industry
Cell Membrane
Tyrosine phosphorylation
030104 developmental biology
chemistry
Immunology
biology.protein
Plasma membrane Ca2+ ATPase
Calcium
CRISPR-Cas Systems
business
Chickens
030215 immunology
Subjects
Details
- Language :
- English
- ISSN :
- 19492553
- Volume :
- 7
- Issue :
- 35
- Database :
- OpenAIRE
- Journal :
- Oncotarget
- Accession number :
- edsair.doi.dedup.....9810929df0c02d4b3eb9bf19069ec43b