Cdc42 - A signal coordinator in hematopoietic stem cell maintenance

Maintenance of a relatively quiescent cell cycle state is a distinct characteristic of adult hematopoietic stem cells (HSCs) residing in the bone marrow ( BM) microenvironment. This property is considered critical for HSCs to fulfill long term self-renewal and multi lineage differentiation potential throughout mammalian life span. To date, the mechanisms regulating the cell cycle state and the retention of HSCs in the BM microenvironment remain unclear. Cdc42, a small GTPase of the Rho family known to control various cellular functions including adhesion, migration, transcription, and growth, is shown recently in a conditional gene-targeted mouse model to coordinate HSC quiescence maintenance and BM niche residency. The study also highlights a cell-type specific role of Cdc42 in cell cycle regulation.