Figure 1. Merg1a K⁺ channel is expressed in atrophic gastrocnemius muscles of cachectic and hindlimb-suspended mice.

A) Merg1a channel protein isoforms are detected in gatrocnemius muscles of mice experiencing atrophy as a result of malignant tumor growth.

Western blot of membrane protein fractions from brain (lane 1 positive control, 15 µg), control mouse gastrocnemius muscle (pooled muscles of 8 mice; lanes 2 and 3, 50 and 44 µg, respectively) and tumor-expressing mouse gastrocnemius muscle (pooled muscles of 8 mice; lane 4, 44 µg).

B) Merg1a proteins are detected in gastrocnemius muscles of hindlimb-suspended mice.

Western blot of membrane proteins from brain (lane 1 positive control, 15 µg), skm from suspended mice (pooled muscles of 10 mice; lane 2, 60 µg), and skm from wt-bearing mice (pooled muscles of 10 mice; lane 3, 60 µg).

C) Low levels of Merg1a protein are detected in skm of wt-bearing mice.

Western blot of membrane protein fractions from control mouse gastrocnemius muscle concentrated fourfold (lane 1, 70 µg) and from brain sample (lane 2, 15 µg).

D) Merg1a K⁺ channel protein is located in sarcolemmal membranes of skeletal muscle from hindlimb-suspended mice. Representative muscle sections from animals suspended for 4 (panel 1) and 7 (panel 2) d and immunostained with erg1 Ab. Representative muscle section (immunostained with erg1 Ab) from a wt-bearing animal (panel 3). Representative muscle section from suspended (4 d) mouse immunostained without erg1 Ab (panel 4) as control.