Structural and regulatory roles of muscle ankyrin repeat protein family in skeletal muscle.
The biological response of muscle to eccentric contractions (ECs) results in strengthening and protection from further injury. However, the cellular basis for this response remains unclear. Previous studies identified the muscle ankyrin repeat protein (MARP) family, consisting of cardiac ankyrin repeat protein (CARP), ankyrin repeat domain 2/ankyrin repeat protein with PEST and proline-rich region (Ankrd2/Arpp), and diabetes-associated ankyrin repeat protein (DARP), as rapidly and specifically upregulated in mice after a single bout of EC. To determine the role of these genes in skeletal muscle, a survey of skeletal muscle structural and functional characteristics was performed on mice lacking all three MARP family members (MKO). There was a slight trend toward MKO muscles having a slower fiber type distribution but no differences in muscle fiber size. Single MKO fibers were less stiff, tended to have longer resting sarcomere lengths, and expressed a longer isoform of titin than their wild-type counterparts, indicating that these proteins may play a role in the passive mechanical behavior of muscle. Finally, MKO mice showed a greater degree of torque loss after a bout of ECs compared with wild-type mice, although they recovered from the injury with the same or even improved time course. This recovery was associated with enhanced expression of the muscle regulatory genes MyoD and muscle LIM protein (MLP), suggesting that the MARP family may play both important structural and gene regulatory roles in skeletal muscle.
Barash
Ilona A
IA
Dept. of Orthopaedics, University of California, Department of Veterans Affairs Medical Center, San Diego, CA 92161, USA.
Bang
Marie-Louise
ML
Mathew
Liby
L
Greaser
Marion L
ML
Chen
Ju
J
Lieber
Richard L
RL
D000818:Animals; D017089:Ankyrin Repeat; D064211:Connectin; D004548:Elasticity; D005260:Female; D005786:Gene Expression Regulation; D005838:Genotype; D060588:LIM Domain Proteins; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009119:Muscle Contraction; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D009124:Muscle Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism*; D017570:MyoD Protein / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D011494:Protein Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012038:Regeneration / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012518:Sarcomeres / Q000378:metabolism; D019415:Torque
C104844:Ankrd1 protein, mouse; C485877:Ankrd2 protein, mouse; D064211:Connectin; C472288:DARP protein, mouse; D060588:LIM Domain Proteins; D009124:Muscle Proteins; D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; D009687:Nuclear Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; C090114:cysteine and glycine-rich protein 3; D011494:Protein Kinases