Molecular roles of PTPN13 and FRMPD2
The importance of multi-PDZ domain proteins in cell polarity is well established and a crucial role of polarity proteins in tumorigenesis is becoming more and more apparent. This project aims at the functional characterization of two novel protein complexes established via the multi-PDZ domain proteins PTPN13 and the recently identified FRMPD2 protein, respectively. PTPN13 and FRMPD2 are closely related and represent member of a small family of peripheral membrane proteins containing multiple PDZ (PSD-95/Drosophila Discs Large/Zonula Occlundens) domains as well as a FERM (Four-point-one/Ezrin/Radixin/Moesin) domain. Both proteins are strongly expressed in epithelial cells. PTPN13 assembles an apical protein complex, whereas FRMPD2 organizes a protein complex at the basolateral membrane in epithelial cells. PTPN13 is involved in carcinogenesis and mediates resistance to Fas induced apoptosis by an unknown mechanism. FRMPD2 has recently been identified by our group and plays a role in cell/cell adhesion regulation. We are identifying PTPN13- and FRMPD2- protein complexes suggesting a potential role in intracellular membrane trafficking for both proteins.
