UCP2 and UCP3 rise in starved rat skeletal muscle but mitochondrial proton conductance is unchanged

FEBS Lett. 1999 Dec 3;462(3):257-60. doi: 10.1016/s0014-5793(99)01540-9.


The relationship between UCP2 and UCP3 expression and mitochondrial proton conductance of rat skeletal muscle was examined. Rats were starved for 24 h and the levels of UCP2 and UCP3 mRNA and UCP3 protein were determined by Northern and Western blots. Proton conductance was measured by titrating mitochondrial respiration rate and membrane potential with malonate. Starvation increased UCP2 and UCP3 mRNA levels more than 5-fold and 4-fold, respectively, and UCP3 protein levels by 2-fold. However, proton conductance remained unchanged. These results suggest either that Northern and Western blots do not reflect the levels of active protein or that these UCPs do not catalyse the basal proton conductance in skeletal muscle mitochondria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Northern
  • Blotting, Western
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Electrophysiology
  • Female
  • Food Deprivation
  • Ion Channels
  • Kinetics
  • Membrane Transport Proteins*
  • Mitochondria / metabolism*
  • Mitochondrial Proteins*
  • Muscle, Skeletal / metabolism*
  • Proteins / genetics
  • Proteins / metabolism*
  • Protons*
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Wistar
  • Uncoupling Agents / metabolism*
  • Uncoupling Protein 2
  • Uncoupling Protein 3


  • Carrier Proteins
  • Ion Channels
  • Membrane Transport Proteins
  • Mitochondrial Proteins
  • Proteins
  • Protons
  • RNA, Messenger
  • Ucp2 protein, rat
  • Ucp3 protein, rat
  • Uncoupling Agents
  • Uncoupling Protein 2
  • Uncoupling Protein 3