Furthermore, phospho-GSK3β-Ser9 levels were significantly increased in PBECs from COPD stage GOLD IV patients (1.57 ± 0.10, P < 0.05) and control smokers (1.57 ± 0.10, P < 0.05) compared with nonsmoking individuals (1.05 ± 0.05; Fig. 1D) without significant differences in total GSK3β levels (Fig. 1E). Here, GSK3B is linked to chronic obstructive pulmonary disease.