Glomerulosa cell--a unique sensor of extracellular K+ concentration.
The adrenal glomerulosa cells is the cell type most sensitive to extracellular K+ in the mammalian organism. Its sensitivity to physiological increases in K+ concentration ([K+]) is due to the expression of the two-pore domain K+ channels TASK that gives rise to K+ conductance in the range of resting membrane potential (approximately equal to -80mV) and to mechanisms that reduce the activation threshold of T-type voltage-activated Ca2+ channels. Potassium-induced cytoplasmic Ca2+ signal activates adenylyl cyclase; induces and activates StAR, the protein that carries cholesterol to the inner mitochondrial membrane and also enhances the expression of aldosterone synthase. The cytoplasmic Ca2+ signal is transferred into the mitochondrial matrix and enhances the reduction of mitochondrial pyridine nucleotides.
Spät
András
A
Department of Physiology, Laboratory of Cellular and Molecular Physiology, Faculty of Medicine, Semmelweis University and Hungarian Academy of Sciences, P.O. Box 259, H-1444 Budapest, Hungary. spat@puskin.sote.hu
D000818:Animals; D020013:Calcium Signaling / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D005110:Extracellular Space / Q000502:physiology; D006801:Humans; D008564:Membrane Potentials / Q000502:physiology; D008928:Mitochondria / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011188:Potassium / Q000378:metabolism*; D024683:Potassium Channels, Tandem Pore Domain / Q000378:metabolism*; D011742:Pyrimidine Nucleotides / Q000378:metabolism; D015384:Zona Glomerulosa / Q000502:physiology*; D000098682:Steroidogenic Acute Regulatory Protein
D010750:Phosphoproteins; D024683:Potassium Channels, Tandem Pore Domain; D011742:Pyrimidine Nucleotides; D000098682:Steroidogenic Acute Regulatory Protein; D011188:Potassium