Partitioning defective 6 homolog beta, also known as PARD6B, is a member of the PAR6 family and encodes a protein with a PSD95/Discs-large/ZO1 (PDZ) domain, an OPR domain and a semi-Cdc42/Rac interactive binding (CRIB) domain. Cellular asymmetry is critical for the development of multicellular organisms. PARD (partitioning-defective) proteins play important roles in asymmetric cell division and polarized growth, whereas Cdc42 and Rac mediate establishment of cell growth and polarity and contribute to oncogenic transformation by Ras. It is expressed in pancreas and in both adult and fetal kidney, and is weakly expressed in placenta and lung. Recombinant human PARD6B protein, fused to His-tag at N-terminus, was expressed in E.coli.