STRING 9.05 
RUNX2 [ENSP00000352514]
runt-related transcription factor 2; Transcription factor involved in osteoblastic differentiation and skeletal morphogenesis. Essential for the maturation of osteoblasts and both intramembranous and endochondral ossification. CBF binds to the core site, 5'- PYGPYGGT-3', of a number of enhancers and promoters, including murine leukemia virus, polyomavirus enhancer, T-cell receptor enhancers, osteocalcin, osteopontin, bone sialoprotein, alpha 1(I) collagen, LCK, IL-3 and GM-CSF promoters (By similarity). Inhibits MYST4-dependent transcriptional activation
SMAD6 [ENSP00000288840]
SMAD family member 6; Antagonist of signaling by TGF-beta (transforming growth factor) type 1 receptor superfamily members; has been shown to inhibit selectively BMP (bone morphogenetic proteins) signaling by competing with the co-SMAD SMAD4 for receptor-activated SMAD1. SMAD6 is an inhibitory SMAD (I-SMAD) or antagonistic SMAD. Binds to regulatory elements in target promoter regions
Evidence suggesting a functional link:
Neighborhood in the Genome:  
none / insignificant.
Gene Fusions:  
none / insignificant.
Cooccurence Across Genomes:  
none / insignificant.
none / insignificant.
Experimental/Biochemical Data:   yes (score 0.621). In addition, putative homologs were found interacting in other species (score 0.101).  
Association in Curated Databases:  
none / insignificant.
Co-Mentioned in PubMed Abstracts:   yes (score 0.167). In addition, putative homologs are mentioned together in other species (score 0.195).  
Combined Score:
Evidence for specific actions:
Activation:yes (score: 0.152)  
Binding:yes (score: 0.207)