gene inserted into the phosphatase domain of the murine PTPkappa (PTPRK) gene, Shen and colleagues determined the detailed expression pattern of endogenous PTPRK. β-gal activity was observed in many areas of the adult forebrain, including layers II and IV, and to a lesser extent in layer VI of the cortex. β-gal activity was also observed in apical dendrites of cortical pyramidal cells, the granule layer of the olfactory and accessory olfactory bulbs, the anterior hypothalamus, paraventricular nucleus, and in granule and pyramidal layers of the dentate gyrus and CA 1-3 regions of the hippocampus. In the midbrain, β-gal was observed in the subthalamic nucleus, the superior and inferior colliculi and in the red nucleus. β-gal activity was also observed in the neural retina, in the inner nuclear layer and in small ganglion cells of the ganglion cell layer. Interactions PTPRK has been shown to interact with: Beta-catenin, E-cadherin (CDH-1), Epidermal growth factor receptor (EGFR), HER2, Plakoglobin, and α-catenin. References Further reading