a member of the TNF-receptor superfamily. This receptor for CD40L mediates a broad variety of immune and inflammatory responses including T cell-dependent immunoglobulin class switching, memory B cell development, and germinal center formation. Defects in CD40 are the cause of hyper-IgM immunodeficiency type 3 (HIGM3). HIGM3 is an autosomal recessive disorder which includes an inability of B cells to undergo isotype switching, one of the final differentiation steps in the humoral immune system, an inability to mount an antibody-specific immune response, and a lack of germinal center formation. Two alternatively spliced isoforms have been reported. Isoform I is a type I membrane protein; isoform II is secreted. Note: This description may include information from UniProtKB.
Protein type: Receptor, cytokine; Membrane protein, integral
Cellular Component: intracellular membrane-bound organelle; integral to plasma membrane; extracellular region; plasma membrane; external side of plasma membrane
Molecular Function: signal transducer activity; protein binding; enzyme binding; ubiquitin protein ligase binding; receptor activity
Biological Process: B cell proliferation; positive regulation of isotype switching to IgG isotypes; platelet activation; regulation of immune response; positive regulation of I-kappaB kinase/NF-kappaB cascade; positive regulation of interleukin-12 production; immune response-regulating cell surface receptor signaling pathway; activation of NF-kappaB transcription factor; cellular calcium ion homeostasis; positive regulation of MAP kinase activity; positive regulation of tyrosine phosphorylation of Stat1 protein; positive regulation of Cdc42 GTPase activity; positive regulation of B cell proliferation; positive regulation of transcription from RNA polymerase II promoter; positive regulation of Rac GTPase activity; protein complex assembly; positive regulation of protein amino acid phosphorylation; inflammatory response; defense response to virus; regulation of immunoglobulin secretion
SS: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.