IGHG1

Function

Constant region of immunoglobulin heavy chains. Immunoglobulins, also known as antibodies, are membrane-bound or secreted glycoproteins produced by B lymphocytes. In the recognition phase of humoral immunity, the membrane-bound immunoglobulins serve as receptors which, upon binding of a specific antigen, trigger the clonal expansion and differentiation of B lymphocytes into immunoglobulins-secreting plasma cells. Secreted immunoglobulins mediate the effector phase of humoral immunity, which results in the elimination of bound antigens (PubMed:20176268, PubMed:22158414). The antigen binding site is formed by the variable domain of one heavy chain, together with that of its associated light chain. Thus, each immunoglobulin has two antigen binding sites with remarkable affinity for a particular antigen. The variable domains are assembled by a process called V-(D)-J rearrangement and can then be subjected to somatic hypermutations which, after exposure to antigen and selection, allow affinity maturation for a particular antigen (PubMed:17576170, PubMed:20176268). Mediates IgG effector functions on monocytes triggering ADCC of virus-infected cells.

Involvement in disease

Multiple myeloma

MM

A malignant tumor of plasma cells usually arising in the bone marrow and characterized by diffuse involvement of the skeletal system, hyperglobulinemia, Bence-Jones proteinuria and anemia. Complications of multiple myeloma are bone pain, hypercalcemia, renal failure and spinal cord compression. The aberrant antibodies that are produced lead to impaired humoral immunity and patients have a high prevalence of infection. Amyloidosis may develop in some patients. Multiple myeloma is part of a spectrum of diseases ranging from monoclonal gammopathy of unknown significance (MGUS) to plasma cell leukemia.

None

The disease is caused by variants affecting the gene represented in this entry. A chromosomal aberration involving IGHG1 is found in multiple myeloma. Translocation t(11;14)(q13;q32) with the IgH locus. Translocation t(11;14)(q13;q32) with CCND1; translocation t(4;14)(p16.3;q32.3) with FGFR3; translocation t(6;14)(p25;q32) with IRF4.

Post-translational modifications

Glycosylation on Asn-180 is required for interaction with Fc receptors and ability to activate the complement pathway.

(Microbial infection) Deglycosylation on Asn-180 by S.pyogenes EndoS or Endos2 endoglucosidases prevents interaction between immunoglobulin-gamma (IgG) and Fc receptors, impairing ability to activate the complement pathway.

Cellular localization

• Isoform 1
• Secreted
• Isoform 2
• Cell membrane
• Single-pass membrane protein

Alternative names

Immunoglobulin heavy constant gamma 1, Ig gamma-1 chain C region, Ig gamma-1 chain C region EU, Ig gamma-1 chain C region KOL, Ig gamma-1 chain C region NIE, IGHG1

Database links

swissprot:P01857 swissprot:Q569F4 entrezGene:3492 swissprot:Q6PJA4 swissprot:Q6PJ95 swissprot:Q7Z5W1 swissprot:Q7Z7P5 swissprot:Q6GMX1 swissprot:Q6IN78 swissprot:P01860 swissprot:P01859 swissprot:P01871 swissprot:P01861 omim:147130 omim:147120 entrezGene:3500 omim:147110 omim:147100 omim:147020 entrezGene:3501 entrezGene:3502 entrezGene:3503 entrezGene:3507 swissprot:Q6GMX6