Interleukin-15 (IL 15) Human Active Protein

The protein encoded by this gene is a cytokine that regulates T and natural killer cell activation and proliferation. This cytokine and interleukine 2 share many biological activities. They are found to bind common hematopoietin receptor subunits, and may compete for the same receptor, and thus negatively regulate each other's activity. The number of CD8+ memory cells is shown to be controlled by a balance between this cytokine and IL2. This cytokine induces the activation of JAK kinases, as well as the phosphorylation and activation of transcription activators STAT3, STAT5, and STAT6. Studies of the mouse counterpart suggested that this cytokine may increase the expression of apoptosis inhibitor BCL2L1/BCL-x(L), possibly through the transcription activation activity of STAT6, and thus prevent apoptosis. Alternatively spliced transcript variants of this gene have been reported. [provided by RefSeq, Feb 2011]

IL15: Cytokine that stimulates the proliferation of T- lymphocytes. Stimulation by IL-15 requires interaction of IL-15 with components of IL-2R, including IL-2R beta and probably IL-2R gamma but not IL-2R alpha. Belongs to the IL-15/IL-21 family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Cytokine; Secreted; Cell cycle regulation; Secreted, signal peptide

Chromosomal Location of Human Ortholog: 4q31

Cellular Component: nucleoplasm; Golgi apparatus; extracellular space; cell surface; membrane; integral to plasma membrane; cytoplasm; extracellular region; endosome

Molecular Function: protein binding; hematopoietin/interferon-class (D200-domain) cytokine receptor binding; cytokine activity

Biological Process: positive regulation of interleukin-17 production; positive regulation of immune response; NK T cell proliferation; positive regulation of natural killer cell proliferation; negative regulation of smooth muscle cell proliferation; cell maturation; signal transduction; lymph node development; positive regulation of tyrosine phosphorylation of Stat3 protein; positive regulation of natural killer cell differentiation; extrathymic T cell selection; positive regulation of tissue remodeling; skeletal muscle atrophy; cell-cell signaling; natural killer cell differentiation; positive regulation of cell proliferation; positive regulation of T cell proliferation; immune response; regulation of T cell differentiation; regulation of defense response to virus by host; inflammatory response; hyaluronan metabolic process; aging; positive regulation of inflammatory response