Cells were washed 2x with cold PBS and collected with 400 μl cold Buffer A (10 mM Hepes pH 7.9, 10 mM KCl, 0.1 mM EDTA, 0.1 mM EGTA, 1 mM DTT, 0.5 mM PMSF). Nuclei were lysed using 10% NP-40 and nuclear pellet resuspended in cold Buffer C (20 mM Hepes pH 7.9, 0.4 M NaCl, 1 mM EDTA, 1 mM EGTA, 1 mM DTT, 1 mM PMSF). Nuclear extracts were collected by centrifugation, separated using 10% SDS-PAGE, transferred and immunoblotted for TDG (Genetex, GT622), and Lamin A/C (EMD Millipore). Alternatively, whole cell lysates were collected using RIPA buffer, separated using 10% or 12.5% SDS-PAGE and then immunoblotted for integrin β4 (BD Transduction Labs, #611232), laminin γ2 chain for laminin-5 (Millipore, clone D4B5) or β-actin (Sigma-Aldrich). Uncropped﻿ western blot images can be found in the supplemental information.