Interleukin-16 stimulates a migratory response in CD4+ lymphocytes, monocytes, and eosinophils. Primes CD4+ T-cells for IL-2 and IL-15 responsiveness. Also induces T-lymphocyte expression of interleukin 2 receptor. Ligand for CD4. Isoform 1 may act as a scaffolding protein that anchors ion channels in the membrane. Isoform 3 is involved in cell cycle progression in T-cells. Appears to be involved in transcriptional regulation of SKP2 and is probably part of a transcriptional repression complex on the core promoter of the SKP2 gene. May act as a scaffold for GABPB1 (the DNA-binding subunit the GABP transcription factor complex) and HDAC3 thus maintaining transcriptional repression and blocking cell cycle progression in resting T-cells.
Isoform 3 is expressed in hemopoietic tissues, such as resting T-cells, but is undetectable during active T cell proliferation.
Contains 4 PDZ (DHR) domains.
Isoform 3 is synthesized as a chemo-attractant inactive precursor in hemopoietic tissues and is proteolytically cleaved by caspase-3 to yield IL-16.