Polycystin cation channel PKD1 (IPR006228) is a polycystin cation channel (PCC). Researchers have demonstrated the function of polycystin-L as a cation channel (Na, K, and Ca++2+), activated by Ca2+. Two members of the PCC family, polycystin 1 and 2, undergo mutations in autosomal dominant polycystic kidney disease, while mice with kidney and retinal defects lack polycystin-L. UPAR (IPR031424), UPAR/Ly6 domain Quiver-like protein, also known as Sleepless protein or SSS, is a glycosylphosphatidylinositol (GPI)-anchored Ly-6 family protein that is important for maintaining a healthy sleep cycle, both when you're not getting enough sleep and when you are. It is a small protein, weighing approximately 15 kDa. SSS is a novel potassium channel subunit that regulates the voltage-gated potassium channel Shaker (Sh) protein, a potassium channel that is responsible for sleep. This interaction inhibits neural excitability, thereby facilitating sleep. SSS antagonizes nicotinic acetylcholine receptors (nAChRs) in addition to Sh regulation to promote sleep and reduce synaptic transmission.