Transcription of the ITGAL (CD11a) gene, is stimulated by binding of RUNX3, presumably in complex with CBFB, to the ITGAL promoter. ITGAL is a leukocyte integrin involved in transendothelial migration of leukocytes during immune and inflammatory responses as well as co-stimulation of T cells. RUNX3, as well as RUNX1, positively regulate integrin alpha 4 (ITGA4, also known as CD49d) expression. A RUNX binding site exists in the ITGA4 promoter, but the direct regulation by RUNX transcription factors has not been demonstrated (Domniguez-Soto et al. 2005).