Elevated temperatures enhance KCCl activity in sickle cells.

The maintenance of red blood cell volume is important in the pathophysiology of sickle cell disease. The KCl cotransporter (KCCl) is capable of mediating sickle cell dehydration. In this study, we have determined the effect of increased temperature (over the range 37-41 degrees C) on basal K+ transport and K+ transport following activation of KCCl by urea or N-ethylmaleimide (NEM). An increased temperature was found to have only a small effect (approximately a 20% increase) on basal K+ transport. In contrast, the increase was much greater (about 60%) after activation of KCCl by urea. Following activation of KCCl by NEM, the increase in K+ transport with increasing temperature was small (about 10%). This suggests that it is the signalling system rather than the transporter itself that is sensitive to temperature.