This is my terrible attempt to analogize Huxley's sliding filament theory. I used to think of the sliding filament theory story of love, betrayal, and violence. It makes it seem super interesting right? I thought I'd write a little narrative of how the story would play out. I promise to actually explain the theory soon. I hope in the meantime this entertains you. For those of you who already understand the sliding filament theory, I really hope you enjoy this and can draw the parallels quite easily.
It's a normal day in Sarcomere, the core of Muscle city. A couple, myosin and tropinin - known affectionately as tropomyosin by their friends. are walking to neuromuscular junction, the train station because there's supposed to be some big event. They're joined by the brothers, adenosine-triphosphate and inorganic phosphate, who like to be called ADP and Pi. When they get to the junction they find out that the thugs, acetylcholine (ACh) is coming to town on the fastest train around, the nerve impulse. Everyone is pretty, ACh also cause trouble wherever they go. The train pulls into the station, ACh gets off and immediately wreck the joint, they smash a transformer and turn out all the lights.
Word reaches sarcoplasmic reticulum, the favourite hangout of the notorious calcium, who likes to be known as Ca+. Ca+ is a bigwig in sarcomere and he doesn't like it when a stranger comes and starts to cause trouble. Wasting no time, Ca+ rushing in sarcomere. This is where the story gets really heated.
You see, Troponin has always had huge crush on Ca+, like head-over-heels in love with him, so when troponin sees Ca+, with his pearly white smile, she ditches myosin on the spot. Myosin, although heartbroken, isn't long seeking out a new partner. He's had his eye on Actin, a beautiful girl who lives on the over side of the river. ADP and Pi come up with a cunning plan - they tell myosin he should build a bridge across the river, there's no way that actin could resist such a committed act. Myosin gets straight to work and builds a bridge. Actin, touched by the gesture mets Myosin and the bridge - it was love at first site. They name they bridge the actin-myosin cross bridge. Myosin sweeps the lovely actin of her feet with one powerfullstroke. ADP and Pi, not wanting to be third wheels go on their merry way.
It seems that their love will never end, however, what myosin didn't tell actin is that the real reason troponin left him for calcium is because myosin is a two-timing bastard. It seems that he had himself a little piece on the side, her name is adenosine-triphosphate (ATP). When she finds out that myosin and troponin split up she rushes over to claim her man all for herself. Stumbling in on myosin and actin in the throws of passion she becomes furious. Fuelled with rage, she charges with malice in heart and socks actin square in her face. Myosin is powerless to stop ATP because he's so exhausted - what with hectic day he had losing one lover, building a bridge and getting busy with actin. In such a low-energy state myosin forgets all about losing troponin and realizes that actin was just a hook-up on the rebound. All he really wants to do now is go home with his one true love ATP.
ATP brings her man home as Actin is left wondering what the hell just happened. Unfortunately for ATP, Myosin never learns from his mistakes. He can't get Troponin off his mind so he decides to giver her a call. Apparently Ca+ was actually a pretty big douche. Myosin figures it can hurt to invite Troponin over just to "chill" with him and his old pals ADP and Pi. When she comes over it's as if they had never been apart.