title: (Na+ + K+)-ATPase is a target for phosphoinositide 3-kinase/protein kinase B and protein kinase C pathways triggered by albumin.
abstract: In recent decades, evidence has confirmed the crucial role of albumin in the progression of renal disease. However, the possible role of signaling pathways triggered by physiologic concentrations of albumin in the modulation of proximal tubule (PT) sodium reabsorption has not been considered. In the present work, we have shown that a physiologic concentration of albumin increases the expression of the α1 subunit of (Na(+) + K(+))-ATPase in LLC-PK1 cells leading to an increase in enzyme activity. This process involves the sequential activation of PI3K/protein kinase B and protein kinase C pathways promoting inhibition of protein kinase A. This integrative network is inhibited when albumin concentration is increased, similar to renal disease, leading to a decrease in the α1 subunit of (Na(+) + K(+))-ATPase expression. Together, the results indicate that variation in albumin concentration in PT cells has an important effect on PT sodium reabsorption and, consequently, on renal sodium excretion.
authors: Instituto de Biofísica Carlos Chagas Filho/Universidade Federal Rio de Janeiro, Centro de Ciências da Saúde, Bloco G, 21949-900 Rio de Janeiro, Brazil.
authors: Diogo B
authors: DB
authors: Peruchetti
authors: Ana Acacia S
authors: AA
authors: Pinheiro
authors: Sharon S
authors: SS
authors: Landgraf
authors: Mira
authors: M
authors: Wengert
authors: Christina M
authors: CM
authors: Takiya
authors: William B
authors: WB
authors: Guggino
authors: Celso
authors: C
authors: Caruso-Neves
mesh_terms: D000418:Albumins / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D017136:Ion Transport; D007674:Kidney Diseases / Q000201:enzymology / Q000473:pathology; D007687:Kidney Tubules, Proximal / Q000201:enzymology* / Q000473:pathology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013552:Swine
chemical_list: D000418:Albumins; D019869:Phosphatidylinositol 3-Kinases; D011493:Protein Kinase C; D051057:Proto-Oncogene Proteins c-akt; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase