The nuclear pore complex (NPC) trafficks cargo across the nuclear membrane. Nucleoprotein TPR functions as a scaffolding element in the nuclear phase of the NPC essential for normal nucleocytoplasmic transport of proteins and mRNAs. The complex glucokinase (GCK1) and glucokinase regulatory protein (GKRP) can be translocated to the nucleus via the NPC. Defects in TPR may confer susceptibility towards thyroid papillary carcinona (TPC; MIM:18850), a common tumor of the thyroid that typically arises as an irregular, solid or cystic mass from otherwise normal thyroid tissue. Mutations in TPR that can confer susceptibility to TPC are L458P and M489P (Hase et al. 2001, Hase & Cordes 2003).