Can molecular heat pumps explain the intracellular temperature anomaly?

Synopsis

The metabolic processes in living cells generate heat. At the scale of whole organisms, this heating is related to familiar phenomena, such as the regulation of body temperature. At the scale of single cells, it has generally been assumed that temperature gradients are negligible. For example, a common model of cellular heating suggests that the local temperature increase from the interior to the exterior of a single cell should be on the order of 10^-5 ℃ or smaller. However, in recent years a wide variety of temperature probes at the subcellular scale have been developed, and multiple groups have reported that the local temperature increase in single cells lies within 0.1 to 10 ℃. I will reassess the thermodynamic limits of local temperature increase, based on the idea that membrane-bound transport enzymes can act as molecular heat pumps. I will discuss experiments to test this new mechanism, and some potential consequences of intracellular temperature gradients for studies of cellular metabolism.