MAL protein stabilizes luminal membrane PLC β3 and negatively regulates ENaC in mouse cortical collecting duct cells.

MAL protein stabilizes luminal membrane PLCβ3 and negatively regulates ENaC in mouse cortical collecting duct cells. Am J Physiol Renal Physiol. 2019 Jul 31;: Authors: Tuna KM, Liu BC, Yue Q, Ghazi ZM, Ma HP, Eaton DC, Alli AA Abstract Abnormally high epithelial sodium channel (ENaC) activity in the aldosterone sensitive distal nephron and collecting duct leads to hypertension. Mal is a lipid-raft-associated protein that has been previously shown to regulate NKCC2 (Na-K -2Cl co-transporter) and aquaporin-2 in the kidney, but it is not known whether it regulates renal ENaC. ENaC activity is positively regulated by the anionic phospholipid phosphate phosphatidyl inositol 4,5 bis-phosphate (PIP2). Members of the myristoylated alanine rich C kinase substrate (MARCKS) family increase PIP2 concentration at the plasma membrane while hydrolysis of PIP2 by phospholipase C (PLC) reduces PIP2 abundance. Our hypothesis was Mal protein negatively regulates renal ENaC activity by stabilizing phospholipase C protein expression at the luminal plasma membrane. We investigated the association between Mal, MARCKS Like Protein, and ENaC. We show Mal colocalizes with PLCβ3 in lipid rafts and positively regulates its protein expression thereby reducing PIP2 availability at the plasma membrane. Kidneys of 129Sv mice injected with MAL shRNA lentivirus resulted in increased ENaC open probability in split-open renal tubules. Overexpressing Mal protein in mp...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research