Table 2.

Genetic gain- and loss-of-function studies in muscle wasting.

Molecule	Function	Effect on muscle atrophy	References
MAFbx/Atrogin-1	Muscle-specific E3 ligase	Promote	(58)
MuRF-1	Muscle-specific E3 ligase	Promote	(58)
Cbl-b	E3 ligase	Promote	(76)
Calpastatin	Endogenous calpain inhibitor	Protect	(113, 125)
Caspase 3	Protease	Promote	(143)
AKT	Kinase	Protect	(147, 153)
TORC1	Kinase	Promote	(150)
FoxO	Transcription factor	Promote	(95–96, 159–160, 216)
PGC-1α	Transcriptional co-activator	Protect	(165)
JunB	Transcription factor	Protect	(217)
NFκB	Transcription factor	Promote	(181–182)
TWEAK	Cytokine	Promote	(171)
ActRIIB	Cytokine receptor	Promote	(193)
Myostatin	Cytokine	Promote	(184–189) (190)