Effects of an occludin second loop peptide (LYHY). A. Transepithelial resistance (TER) recovery following the calcium switch. EDTA was applied for 15 minutes to filter grown Eph4 monolayers that had achieved a TER of 1000 Ohms•cm2, reducing the TER to the baseline of 66 Ohms•cm2. LYHY or LYQY (350 μM) in growth medium containing normal Ca++ and Mg++ was placed above and below the filter supports. The TER was measured at 12 and 24 hours following peptide application (inset). Peptides were washed away 24 hrs following application and the TER measured every 24 hrs thereafter. B. Effect of peptides on occludin distribution in mature Eph4 cell monolayers. EPH4 cells on glass slides were treated with 350 μM LYHY or LYQY for 8 hours then fixed and stained with an anti-occludin antibody. Note the frequent areas of non-junctional occludin in the LYHY treated cells compared to the control LYQY peptide.