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 Meis2B 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. Isoforms Meis2B and Meis2D 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. Monomer and homodimer. Heterodimer with HOXB13 (By similarity). Isoform Meis2A interacts with TLX1. Isoform Meis2B interacts with HOXA13 and PBX1 isoform PBX1b. Isoform Meis2D interacts with SP1, SP3 and KLF4. Isoform Meis2D interacts with PBX1 isoform PBX1a; the interaction partially relieves MEIS2 autoinhibition. Isoform Meis2B is part of a PDX1:PBX1b:MEIS2b complex; Meis2B is recruited by PBX1b and can be replaced by isoform Meis2D in a small fraction of complexes. Can form trimeric complexes including HOXB8 and PBX2 or PBX3. Additional isoforms seem to exist. Displays spatially restricted expression patterns in the developing nervous system, limbs, face, and in various viscera. In adult, it is mainly expressed in the brain and female genital tract, with a different distribution of the alternative splice forms in these organs. Lower expression in lung and only basal level in heart, liver, kidney, spleen, and testis. Expressed in pancreatic islets (beta-cells only) (PubMed:21059917). Expressed at high levels in all stages of embryonic development analyzed (7 days to 17 days). First detected around 10.5 dpc in the developing ventrolateral telencephalon. Is found at moderate levels throughout the ventricle zone (VZ) of the entire telencephalon with the exception of the ventro- and dorso-medial regions. The highest expression is detected in the subventricular zone (SVZ) of the lateral ganglionic eminence (LGE) and developing striatum. By 16.5 dpc, also found in the cortical plate. Also expressed at high levels in the caudal ganglionic eminence (CGE) and amygdala. Expression in the telencephalon remains unchanged at birth and into adulthood. By retinoic acid. Belongs to the TALE/MEIS homeobox family.