Figure 8

Proposed role of FGFR1 in adult skeletal muscle. Increased production of FGFR1 in a weight bearing muscle fiber would result in an increase in protein synthesis and degradation, which would counteract each other and result in no observable increase in muscle fiber size. However, in a fiber undergoing atrophy, increased FGFR1 would not elevate the significant amount of proteolysis that would already be occurring in an atrophying fiber. However, FGFR1 would still elevate protein synthesis in the atrophic fiber, thereby maintaining fiber size and strength.