Skip to main content
. Author manuscript; available in PMC: 2011 Jul 1.
Published in final edited form as: Exerc Sport Sci Rev. 2010 Jul;38(3):135–142. doi: 10.1097/JES.0b013e3181e3734d

Figure 4.

Figure 4

Potential role for minor triadic proteins in low-frequency fatigue (LFF)-induced excitation-contraction uncoupling. A. Prior to LFF the dihydropyridine receptor (DHPR) and ryanodine receptor (RyR1) are functionally coupled. The elongated conformation of the transverse-tubule (t-tubule) is maintained by mitsugumin-29 (Mg-29). Junctophilin-1 and -2 (JP-1/2) maintain the proper alignment between the t-tubule and junctional face protein 45 kDa (JFP-45) is important for the functional expression of the DHPR. B. Disruption of Mg-29 allows the ttubule to adopt a conformation unfavorable to functional coupling of the DHPR and RyR1. C. Loss of JP-1/2 disrupts the alignment between the t-tubule and sarcoplasmic reticulum (SR), uncoupling the DHPR and RyR1. D. Altering the interaction between JFP-45 and the DHPR results in a misalignment of the DHPR and RyR1. The figure depicts the uncoupling as a physical uncoupling but reality the impairment may be a more subtle decrease in the strength of the functional uncoupling.