Involved in transcriptional regulation. Binds to HOX or PBX proteins to form dimers, or to a DNA-bound dimer of PBX and HOX proteins and thought to have a role in stabilization of the homeoprotein-DNA complex. Isoform 3 is required for the activity of a PDX1:PBX1b:MEIS2b complex in pancreatic acinar cells involved in the transcriptional activation of the ELA1 enhancer; the complex binds to the enhancer B element and cooperates with the transcription factor 1 complex (PTF1) bound to the enhancer A element; MEIS2 is not involved in complex DNA-binding. Probably in complex with PBX1, is involved in transcriptional regulation by KLF4. Isoform 3 and isoform 4 can bind to a EPHA8 promoter sequence containing the DNA motif 5'-CGGTCA-3'; in cooperation with a PBX protein (such as PBX2) is proposed to be involved in the transcriptional activation of EPHA8 in the developing midbrain. May be involved in regulation of myeloid differentiation. Can bind to the DNA sequence 5'-TGACAG-3'in the activator ACT sequence of the D(1A) dopamine receptor (DRD1) promoter and activate DRD1 transcription; isoform 5 cannot activate DRD1 transcription. Monomer and homodimer (PubMed:26550823). Heterodimer with HOXB13 (Ref.16). Isoform 2 interacts with TLX1. Isoform 3 interacts with HOXA13 and PBX1 isoform PBX1b. Isoform 4 interacts with SP1, SP3 and KLF4. Isoform 4 and isoform 5 interact with PBX1 isoform PBX1a; the interaction partially relieves MEIS2 autoinhibition. Isoform 3 also known as MEIS2b is part of a PDX1:PBX1b:Meis2B complex; Meis2B is recruited by PBX1b and can be replaced by isoform 4 in a small fraction of complexes. Can form trimeric complexes including HOXB8 and PBX2 or PBX3. Expressed in various tissues. Expressed at high level in the lymphoid organs of hematopoietic tissues. Also expressed in some regions of the brain, such as the putamen. Expressed in the proliferative zones of the fetal neocortex. Expressed at a very high level in the developing ganglionic eminence and at a more moderate level in the cortical plate. The disease is caused by variants affecting the gene represented in this entry. Belongs to the TALE/MEIS homeobox family.