The nucleolar targeting signal (NTS) of parathyroid hormone related protein mediates endocytosis and nucleolar translocation.

Previous work has identified the parathyroid hormone-related protein (PTHrP) nucleolar targeting signal (NTS) as both necessary and sufficient for localization of PTHrP to the nucleus and nucleolus of a variety of cells where it is believed to participate in the regulation of cell proliferation, differentiation, and apoptotic cell death. The mechanism whereby a secreted peptide, such as PTHrP, gains access to the nuclear compartment remains a question of debate. The current work examines the possibility that exogenous PTHrP is internalized and transported to the nuclear compartment by a mechanism that is dependent on preservation of the PTHrP NTS.