Interleukin-4 Protein (IL4) Human Active Protein

The protein encoded by this gene is a pleiotropic cytokine produced by activated T cells. This cytokine is a ligand for interleukin 4 receptor. The interleukin 4 receptor also binds to IL13, which may contribute to many overlapping functions of this cytokine and IL13. STAT6, a signal transducer and activator of transcription, has been shown to play a central role in mediating the immune regulatory signal of this cytokine. This gene, IL3, IL5, IL13, and CSF2 form a cytokine gene cluster on chromosome 5q, with this gene particularly close to IL13. This gene, IL13 and IL5 are found to be regulated coordinately by several long-range regulatory elements in an over 120 kilobase range on the chromosome. Two alternatively spliced transcript variants of this gene encoding distinct isoforms have been reported. [provided by RefSeq, Jul 2008]

IL4: Participates in at least several B-cell activation processes as well as of other cell types. It is a costimulator of DNA-synthesis. It induces the expression of class II MHC molecules on resting B-cells. It enhances both secretion and cell surface expression of IgE and IgG1. It also regulates the expression of the low affinity Fc receptor for IgE (CD23) on both lymphocytes and monocytes. Genetic variations in IL4 may be a cause of susceptibility to ischemic stroke (ISCHSTR); also known as cerebrovascular accident or cerebral infarction. A stroke is an acute neurologic event leading to death of neural tissue of the brain and resulting in loss of motor, sensory and/or cognitive function. Ischemic strokes, resulting from vascular occlusion, is considered to be a highly complex disease consisting of a group of heterogeneous disorders with multiple genetic and environmental risk factors. Belongs to the IL-4/IL-13 family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Cell cycle regulation; Cytokine; Motility/polarity/chemotaxis; Secreted; Secreted, signal peptide

Chromosomal Location of Human Ortholog: 5q31.1

Cellular Component: extracellular region; extracellular space

Molecular Function: interleukin-4 receptor binding; protein binding

Biological Process: B cell differentiation; cellular defense response; chemotaxis; cholesterol metabolic process; connective tissue growth factor biosynthetic process; immune response; myeloid dendritic cell differentiation; negative regulation of apoptosis; negative regulation of osteoclast differentiation; negative regulation of transcription, DNA-dependent; positive regulation of B cell proliferation; positive regulation of interleukin-13 production; positive regulation of isotype switching to IgE isotypes; positive regulation of isotype switching to IgG isotypes; positive regulation of MHC class II biosynthetic process; positive regulation of T cell differentiation; positive regulation of T cell proliferation; positive regulation of transcription from RNA polymerase II promoter; positive regulation of transcription, DNA-dependent; regulation of immune response; regulation of isotype switching; regulation of phosphorylation; T-helper 2 type immune response

Disease: Stroke, Ischemic