The multifunctional or moonlighting protein CD26/DPPIV.
CD26/DPPIV can be considered a moonlighting protein because it is a multifunctional protein that exerts its different functions depending on cell type and intra- or extracellular conditions in which it is expressed. In the present review, we summarize all its known functions in relation to physiological and pathophysiological conditions. The protein is a proteolytic enzyme, receptor, costimulatory protein, and is involved in adhesion and apoptosis. The CD26/DPPIV protein plays a major role in immune response. Abnormal expression is found in the case of autoimmune diseases, HIV-related diseases and cancer. Natural substrates for CD26/DPPIV are involved in immunomodulation, psycho/neuronal modulation and physiological processes in general. Therefore, targeting of CD26/ DPPIV and especially its proteolytic activity has many therapeutic potentials. On the other hand, there are homologous proteins with overlapping proteolytic activity, which thus may prevent specific modulation of CD26/DPPIV. In conclusion, CD26/DPPIV is a protein present both in various cellular compartments and extracellularly where it exerts different functions and thus is a true moonlighting protein.
Boonacker
Emil
E
Academic Medical Center, University of Amsterdam, Department of Cell Biology and Histology, Amsterdam, The Netherlands.
Van Noorden
Cornelis J F
CJ
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001327:Autoimmune Diseases / Q000503:physiopathology; D002448:Cell Adhesion / Q000502:physiology; D018819:Dipeptidyl Peptidase 4 / Q000502:physiology*; D006801:Humans; D008954:Models, Biological
D018819:Dipeptidyl Peptidase 4