All Phenotypes Cdk5rap1<tm1.2Tomik> MGI Mouse

increased skeletal muscle fiber mitochondrial DNA content ( J:220703 )

• significant increase in relative mtDNA content in skeletal muscle relative to wild-type controls

abnormal mitochondrial crista morphology ( J:220703 )

• a progressive disruption of mitochondrial cristae is occasionally observed in cardiac muscle

• KD-fed mice show more mitochondria with abnormal cristae in skeletal muscle and heart tissues relative to KD-fed wild-type controls

increased mitochondrial size ( J:220703 )

• increased mitochondrial mass in skeletal muscle and abnormally enlarged mitochondria in heart tissue relative to wild-type controls

• marked increase in mitochondrial mass in both tissues after 10 weeks on a ketogenic diet relative to KD-fed wild-type controls

abnormal cell physiology ( J:220703 )

• mass spectrometry revealed no 2-methylthio-N6-isopentenyl adenosine (ms²i⁶A) in total RNA isolated from mutant brain, liver, skeletal muscle and heart tissue

• mitochondrial ms² modification is completely absent at A37 in mt-tRNA^Phe, mt-tRNA^Trp, mt-tRNA^Tyr, and mt-tRNA^Ser(UCN) isolated from mutant mice

• however, cytosolic ms²t⁶A is intact and taum⁵ modification at U34 in mt-tRNA^Trp remains unaffected

abnormal mitophagy ( J:220703 )

• after FCCP treatment, a number of large mitochondrial aggregates are surrounded by the autophagosomal membrane protein LC3, indicating accelerated mitophagy

• after treatment with KD or TAC surgery, a number of cardiac mitochondria are degraded in autophagic vacuoles, unlike in wild-type controls

abnormal mitochondrial physiology ( J:220703 )

• mutant MEFs contain an increased number of mitochondria with very low membrane potentials relative to wild-type MEFs

• after treatment with very low doses of rotenone or FCCP, mutant MEFs show rapid loss of the mitochondrial membrane potential, unlike wild-type MEFs

• KD-fed mice show increased proliferation of both intermyofibrillar and subsarcolemmal mitochondria in skeletal muscle relative to KD-fed wild-type controls

abnormal respiratory electron transport chain ( J:220703 )

• mutant MEFs show substantially decreased incorporation of mitochondrial proteins into complexes I, III and IV, indicating impaired complex assembly

• however, complex V is unaffected

abnormal mitochondrial ATP synthesis coupled electron transport ( J:220703 )

• respiratory control ratio is significantly decreased in mitochondria isolated from mutant skeletal muscle and heart tissue relative to wild-type controls (skeletal muscle: 9.4 versus 6.5; heart: 4.9 versus 3.2)

• steady-state ATP level is significantly lower in mutant skeletal muscle and heart tissue than that in wild-type controls

abnormal oxidative phosphorylation ( J:220703 )

• steady-state levels of complex I and IV are substantially reduced in mitochondria isolated from mutant skeletal muscle and heart tissues

• steady-state levels of complex I and IV proteins are markedly reduced in mutant skeletal muscle and heart tissues

• complex I activity is 58.6% of wild-type levels in skeletal muscle and 51.5% of wild-type levels in heart tissue

• complex III activity is 88.8% of wild-type levels in skeletal muscle and 80.7% of wild-type levels in heart tissue

• complex IV activity is 80.5% of wild-type levels in skeletal muscle and 79.8% of wild-type levels in heart tissue

• after 10 weeks on a ketogenic diet (KD), complex I activity is 48.6% of KD-fed wild-type controls in skeletal muscle and 47.7% of KD-fed wild-type controls in heart tissue; complex III activity is 82.9% (muscle) and 75% (heart) of KD-fed wild-type controls while complex IV activity is 62.9% (muscle) and 57.8% (heart), indicating accelerated OXPHOS defects under stressed conditions

abnormal translation ( J:220703 )

• mutant mouse embryonic fibroblasts (MEFs) show substantially decreased mitochondrial protein synthesis

oxidative stress ( J:220703 )

• mutant MEFs exhibit a slight but significant increase in reactive oxygen species (ROS) level relative to wild-type MEFs

• mice show a moderate increase in protein carbonylation levels and oxidative stress-related gene expression in skeletal muscle and heart tissues relative to wild-type controls

• under stress conditions (KD or TAC for 10 weeks), mice show a moderately higher protein carbonylation level as well as enhanced polyubiquitination and upregulation of proteins involved in the mitochondrial unfolded protein response in cardiac mitochondria relative to stressed wild-type controls

homeostasis/metabolism phenotype ( J:220703 )

N	• chow-fed mice display normal energy expenditure and glucose metabolism relative to wild-type controls • KD-feeding for 10 weeks has no significant effect on energy expenditure or serum metabolic profiles

impaired exercise endurance ( J:220703 )

• in a treadmill test, KD-fed mice show a significantly higher number of falls than KD-fed wild-type controls and become exhausted as early as 30 min into the test

• however, unstressed (chow-fed) mice show normal treadmill performance

increased response of heart to induced stress ( J:220703 )

• at 10 weeks after transverse aortic constriction (TAC), mice show progressive cardiac hypertrophy, as indicated by an increase in heart weight and LVPW thickness relative to TAC-treated wild-type controls (11.3 mg/g body weight versus 7.5 mg/g body weight)

• TAC-treated mice show a continuous decrease in FS% reaching a value of 21.7% by 10 weeks, unlike TAC-treated wild-type controls where FS% drops from 51.2% to 34.5% at 1 week after TAC but remains relatively stable until 10 weeks

abnormal mitophagy ( J:220703 )

• after FCCP treatment, a number of large mitochondrial aggregates are surrounded by the autophagosomal membrane protein LC3, indicating accelerated mitophagy

• after treatment with KD or TAC surgery, a number of cardiac mitochondria are degraded in autophagic vacuoles, unlike in wild-type controls

abnormal translation ( J:220703 )

• mutant mouse embryonic fibroblasts (MEFs) show substantially decreased mitochondrial protein synthesis

decreased circulating glucose level ( J:220703 )

• KD-fed mice exhibit somewhat lower glucose levels than KD-fed wild-type controls

decreased oxygen consumption ( J:220703 )

• mutant MEFs show a significant decrease in the oxygen consumption rate relative to wild-type MEFs

• oxygen consumption elicited by ADP and FCCP is significantly lower in mutant mitochondria than in wild-type mitochondria

abnormal enzyme/coenzyme activity ( J:220703 )

• significant increase in citrate synthase activity in skeletal muscle relative to wild-type controls

cardiac hypertrophy ( J:220703 )

• KD-fed mice exhibit moderate cardiac hypertrophy, as indicated by an increase in heart volume, heart weight, and left ventricle posterior wall (LVPW) thickness relative to KD-fed wild-type controls

• however, unstressed (chow-fed) mice show no apparent cardiac dysfunction

decreased cardiac muscle contractility ( J:220703 )

• KD-fed mice display a significantly lower percentage of fractional shortening (FS%) than KD-fed wild-type controls (34% versus 43%)

• after TAC surgery, mice show a continuous decrease in FS% reaching a value of 21.7% by 10 weeks, unlike in TAC-treated wild-type controls where FS% drops from 51.2% to 34.5% at 1 week after TAC but remains relative stable until 10 weeks

• at 10 weeks after TAC surgery, isolated cardiomyocytes show a significantly reduced contraction rate upon electrical stimulation relative to TAC-treated wild-type cells

decreased calcium uptake by cardiac muscle ( J:220703 )

• at 10 weeks after TAC surgery, isolated cardiomyocytes show a significant decrease in peak calcium influx relative to TAC-treated wild-type cells