How I learned to stop worrying by studying the kinesin protein

How we can decipher meaning from life through the study of kinesin and the Myth of Sisyphus

By Charlotte Tomlinson

How can a little motor protein observed in neuroscience be responsible for our happiness, and how can it help us find meaning in our short lives? The brain is composed of millions of interconnected neurons, or nerve cells. What we call happiness, for instance, is triggered by the release of specific chemicals known as neurotransmitters. Examples of these include dopamine and serotonin which are transported between neurons across synapses in the amygdala. A neuron is a cell in the nervous system that transmits messages, via electrical impulses, to the brain. Neurons contain microtubules; small tubes that are used to transport substances to different parts of the cell. The process of the chemical exchanges involved in creating ‘happiness’ is facilitated by a kinesin motor protein. It walks along microtubules, with the job of transporting proteins that are essential to the health of the cell. Kinesin also transports myosin, an actin motor protein, that helps generate force and movement, and dyneins, motor proteins that go to the negative end of the microtubule. Theoretical modelling shows kinesin seemingly using its two heads as feet, placing one in front of the other, essentially “walking”, like Sisyphus pushing a boulder up a mountain. It transports the huge sack of protein attached to its tail and other myosin and dyneins attached to it along the microtubule. Disruption of the pathway can have serious consequences, including neurological death. This is when an obstruction in the pathway forms, resulting in the kinesin protein being unable to complete its journey. This triggers neurological decay, disease and eventual death.  It can be argued, therefore, that kinesin proteins are responsible for the fulfilment of our happiness, through delivering their serotonin cargo to nerve synapses. One philosopher defined happiness in a different way to scientists. In 1942, French philosopher Albert Camus published a collection of famous existentialist essays; one in particular concerning how we can find meaning in our indifferent world. The Myth of Sisyphus is based on Greek myth and details the exploits of the cruel yet crafty first king of Ephyra. The gods tried to apprehend him for his crimes, such as murdering visitors in his state, but he was clever enough to escape death by tricking the gods on several occasions. When he was finally apprehended, his punishment was to keep rolling a boulder up a hill in Hades, only for it to roll back down to the bottom whenever he neared the top, for eternity. To Camus, this was the perfect illustration of humanity’s search for meaning in an otherwise indifferent universe, suggesting that meaning comes from our choice to embrace what fate gives us, and thus imagine Sisyphus defiant and ‘happy’. So what does this mean for us? Both the kinesin protein and Sisyphus’s entire existence are characterised by the repetition of the same endless task of transporting a piece of cargo - over and over again. Therefore, the function of the kinesin proteins in neuroscience mirror Sisyphus’ punishment.  You could then conclude that happiness itself is the endless completion of a task at a cellular level. If other functions, even at the smallest biochemical level are repetitive and indefinite by nature, then when applied to our own lives, meaning itself must come by deciding to do the opposite. It comes from our choice to find significance despite whatever happens in our short, trivial existence. As these natural processes are designed to repeat small tasks that sustain life, what perhaps therefore gives it meaning is the ability to choose. From Issue 19