Barbara Cannon's data on the UCP1-ablated mice: "non-cannonical" point of view.
The data of Cannon and co-workers on UCP1-ablated mice are interpreted assuming that UCP2 and UCP3 are involved in thermoregulation as fatty acid-dependent uncouplers although they are not sufficient, in the absence of UCP1, for long term maintenance of normal body temperature of mice after sudden and strong decrease in the ambient temperature. I would like to suggest that in brown fat of control mice, UCP1 is present in an amount higher than UCP2 and 3 and, therefore, is able to cause (a) some fatty acid-mediated decrease in proton motive force in resting state and, hence, (b) oxidation of CoQH2 to CoQ which is shown by Klingenberg and coworkers to be cofactor for UCPs. This results in strong uncoupling and thermogenesis mediated by UCP1, 2 and 3. In the UCP1-ablated mice, activity of UCP2 and 3 appears to be insufficient to induce CoQH2 oxidation in resting brown fat mitochondria, which results in hypothermia.
Skulachev
V P
VP
Department of Bioenergetics, A. N. Berlozersky Institute of Physico-Chemical Biology, Moscow State University, Russia. skulach@genebee.mus.su
D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000818:Animals; D001831:Body Temperature / Q000502:physiology; D001833:Body Temperature Regulation; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D007473:Ion Channels; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3
D002352:Carrier Proteins; D005227:Fatty Acids; D007473:Ion Channels; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D011506:Proteins; C000604372:Ucp1 protein, mouse; C000604390:Ucp2 protein, mouse; C000604393:Ucp3 protein, mouse; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3