Promotes integrin-mediated cell adhesion. May stimulate host defense against viruses and tumor cells (By similarity). Homodimers and homomultimers. The multimers form ring-like structures with a diameter of 30-40 nm. Binds LGALS1 and LGALS3. Binds ITGB1, COL4A1, COL5A1, COL6A1, FN1 and NID. Interacts with the gamma-tubulin ring complex (gamma-TuRC), composed of gamma-tubulin, TUBGCP2, TUBGCP3, TUBGCP4, TUBGCP5 and TUBGCP6. The unglycosylated form interacts with PDE4DIP; this interaction, which is PDE4DIP isoform-specific, may connect a pericentrosomal complex, made of AKAP9, CDK5RAP2, EB1/MAPRE1 and PDE4DIP, to the gamma-tubulin ring complex (gamma-TuRC) to promote microtubule assembly and acetylation.