Overview
| Uniprot ID | P01861 |
|---|
| Protein Name | Immunoglobulin heavy constant gamma 4 |
|---|
| Gene Name | IGHG4 |
|---|
| Organism | Homo sapiens |
|---|
Kla Sites from experimental identification
| Position |
Flanking peptide |
| 88 |
YTCNVDHKPSNTKVD |
Function
Constant region of immunoglobulin (Ig) heavy chains. Igs are membrane-bound or secreted glycoproteins produced by B lymphocytes. In the recognition phase of humoral immunity, the membrane-bound Igs serve as receptors, which upon binding to a specific antigen trigger the clonal expansion and differentiation of B lymphocytes into Ig-secreting plasma cells. Secreted Igs known as antibodies mediate the effector phase of humoral immunity by blocking the interaction of infectious antigens with cellular receptors (via the antigen-binding region) and eliciting effector mechanisms that lead to pathogen neutralization (via the constant region) (PubMed:17576170, PubMed:20176268, PubMed:22158414). The antigen-binding region is formed by the variable domain of one heavy chain paired with the variable domain of its associated light chain. Each Ig molecule has two antigen-binding sites with remarkable affinity for a particular antigen due to V-(D)-J rearrangement, somatic hypermutations and affinity maturation of the variable domains upon antigen exposure (PubMed:17576170, PubMed:20176268, PubMed:22158414). The constant region defines the Ig isotype that perform distinct sets of effector functions. B cells diversify and rearrange their Ig constant regions through class-switch recombination, a process by which the constant region is switched from one Ig isotype to another, namely from IgM and IgD to IgG, IgA and IgE (PubMed:17576170, PubMed:20176268, PubMed:22158414). The constant region interacts (via the fragment crystallizable, Fc) with the Fc receptors on innate immune cells to mediate humoral effector functions. Ig gamma-4 (IgG4) isotype does not elicit antibody-dependent cellular cytotoxicity (ADDC) or complement-dependent cytotoxicity (CDC). Instead it is likely involved in immune tolerance mechanisms to allergens and parasites either by blocking IgE-antigen complex formation or by directly inhibiting mast cell degranulation through Fc receptor signaling. In the context of tumorigenesis, it may participate in immunosuppressive mechanisms
Protein Sequence
10
ASTKGPSVFP
20
LAPCSRSTSE
30
STAALGCLVK
40
DYFPEPVTVS
50
WNSGALTSGV
60
HTFPAVLQSS
70
GLYSLSSVVT
80
VPSSSLGTKT
90
YTCNVDHKPS
100
NTKVDKRVES
110
KYGPPCPSCP
120
APEFLGGPSV
130
FLFPPKPKDT
140
LMISRTPEVT
150
CVVVDVSQED
160
PEVQFNWYVD
170
GVEVHNAKTK
180
PREEQFNSTY
190
RVVSVLTVLH
200
QDWLNGKEYK
210
CKVSNKGLPS
220
SIEKTISKAK
230
GQPREPQVYT
240
LPPSQEEMTK
250
NQVSLTCLVK
260
GFYPSDIAVE
270
WESNGQPENN
280
YKTTPPVLDS
290
DGSFFLYSRL
300
TVDKSRWQEG
310
NVFSCSVMHE
320
ALHNHYTQKS
330
LSLSLELQLE
340
ESCAEAQDGE
350
LDGLWTTITI
360
FITLFLLSVC
370
YSATVTFFKV
380
KWIFSSVVDL
390
KQTIVPDYRN
MIRQGA
Gene Ontology
| Classification |
GO ID |
Description |
| Cellular Component |
GO:0072562 |
blood microparticle |
| Cellular Component |
GO:0070062 |
extracellular exosome |
| Cellular Component |
GO:0005576 |
extracellular region |
| Cellular Component |
GO:0005615 |
extracellular space |
| Cellular Component |
GO:0042571 |
immunoglobulin complex, circulating |
| Cellular Component |
GO:0005886 |
plasma membrane |
| Molecular Function |
GO:0003823 |
antigen binding |
| Molecular Function |
GO:0034987 |
immunoglobulin receptor binding |
| Biological Process |
GO:0002250 |
adaptive immune response |
| Biological Process |
GO:0019731 |
antibacterial humoral response |
| Biological Process |
GO:0050853 |
B cell receptor signaling pathway |
| Biological Process |
GO:0006958 |
complement activation, classical pathway |
Reference
[1] Yang Z, Yan C, Ma J, Peng P, Ren X et al.. Lactylome analysis suggests lactylation-dependent mechanisms of metabolic adaptation in hepatocellular carcinoma.. Nat Metab 5(1):61-79. 2023 Jan. PMID: 36593272.