Possible basic and specific functions of plant uncoupling proteins (pUCP)

Evidence has been provided that the plant uncoupling proteins (pUCP) play b asic physiological roles similar to the other uncoupling protein subfamily members (mammalian UCP1,2,3,4 and BMCP) and are effective in the situations of slight uncoupling that leads to: (1) accelerated respiration and metabo lic rates that are beneficial to plant growth and development; (2) decrease d formation of reactive oxygen species in mitochondria; and, (3) mild therm ogenesis, inevitably accompanying the previous two phenomena. Hypotheticall y, specific physiological roles of pUCP such as cut off of ATP synthesis co uld be manifested in connection with climacteric respiratory rise during fr uit ripening, seed dormancy, and plant senescence. pUCP might also facilita te growth under low temperatures, e.g., during seed germination or in roots . The existence of these specific roles is suggested by the immunochemical and functional localization of pUCP in mitochondria of fruits, seeds and ro ots of various plant species.