Our interests in stem cell biology and regenerative medicine mainly revolve around the protein I have spent the last 25-plus years studying, connexin43 (Cx43). Cx43 is the primary protein in gap junctions, a subcellular structure that couples intercellular communication to a cytoplasmic scaffold that coordinates cellular responses to different stimuli including epidermal wounding cardiovascular ischemia and tumorigenesis. Gap junctions are critical at many developmental stages and in response to injury. Specifically, we are interested in understanding the role that Cx43 regulation plays in stem cells and tissue reorganization during epidermal wound repair. Cx43 plays a key role in the initiation of migration and up regulation of proliferation needed to fill in the wound bed – so called re-epithelialization. We study this process using a transgenic mice and human studies. Gap junctions play a key role in regulating sodium and potassium flux between cardiomyocytes and are downregulated during cardiac disease; we have a long-standing collaboration with Mike Laflamme to determine whether modulation of gap junctions can achieve better engraftment of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) post myocardial infarction. We have also studied the role of Cx43 in differentiation of stem cells into definitive endoderm during pancreas development in collaboration in Vincenzino Cirulli. We encouraged and assisted the Allen Institute in the creation of hiPSCs that express one copy of Cx43-GFP that we hope will be useful in further studying the role of Cx43 in stem cell differentiation and cell fate.