Figure 4.Mitochondrial import of the matrix protein ornithine carbamoyltransferase (OCT) is induced to a greater extent after chronic muscle use in young animals. (A) Representative
autoradiograms of precursor (pOCT) and mature (mOCT) OCT after
5 and 20 min of the import reaction timecourse in isolated SS
(top) and IMF (bottom) mitochondrial subfractions harvested from
the control (CON, open bars) and chronically stimulated (STIM, closed
bars) limbs of young and old animals (TL, translation lane without
mitochondria). (B) and (C) Graphical summaries of
the 20 min import data from repeated experiments shown in panel A
(n = 9-12). (D) Western blots of MSF-L and HSP90 in isolated
cytosolic fractions obtained from the control (C) and chronically
stimulated (S) legs of young and old animals. GAPDH was used to
confirm equal loading of protein. (E) Summary of repeated
experiments shown in panel D (n = 5-7). Data represent the
mean ± SEM. * P < 0.05 vs. Young; ¶ P < 0.05 vs. CON.
