Inducible nitric oxide synthase (iNOS): More than an inducible enzyme? Rethinking the classification of NOS isoforms

Nitric oxide (NO) is a critical signaling molecule synthesized from L -arginine by nitric oxide synthase (NOS). The three NOS isoforms—neuronal NOS (nNOS; NOS1), inducible NOS (iNOS; NOS2), and endothelial NOS (eNOS; NOS3)—have traditionally been classified as either constitutive (nNOS and eNOS) or inducible (iNOS). However, this binary classification oversimplifies their functions, particularly by neglecting the physiological roles of iNOS and misrepresenting its involvement in pathological processes. Increasing evidence demonstrates that all three isoforms can exhibit both constitutive and inducible expression. Notably, iNOS is constitutively expressed at low levels in several tissues, including blood,…

• SB
  Shahid Beheshti University of Medical Sciences

  Award: 43014324-1
• NI
  National Institutes of Health

  Award: 2U54MD017979-01A1