PTS and colorectal cancer: In colorectal cancer, nitrosylation of latent TGF-β binding protein 1 (LTBP1), favored by the formation of a macromolecular complex formed by phosphorylated 6-pyruvoyltetrahydropterin synthase (PTPS) and NOS1 in hypoxic conditions, leads to LTBP1 instability by increased ubiquitination and proteasome degradation.