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Regulation of posttranslational modifications of Npt2a (renal type IIa sodium phosphate cotransporter)
Author(s) -
Lederer Eleanor DeLand,
Murray Rebecca,
Lesousky Nina,
Khundmiri Syed Jalal,
Weinman Edward
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.912.10
Subject(s) - biology , microbiology and biotechnology
NpT2a, a proximal tubule apical membrane (AM) protein, plays a critical role in regulation of phosphate homeostasis. We and others have shown that 1) NpT2a is a glycosylated protein, 2) glycosylation is required for translocation to AM, and 3) NHERF1 deficiency causes aberrant AM expression. We hypothesized that NHERF1 associates with NpT2a prior to AM insertion and facilitates glycosylation. To test this hypothesis, we examined NpT2a‐NHERF1 association in Golgi (G) by density gradient centrifugation of opossum kidney cells. Cells transfected with GFP‐NpT2a at 16C showed retention of NpT2a in the G fractions while cells in 37C showed plasma membrane (PM) localization. NHERF1 was present in both G and PM fractions at both temperatures. NpT2a IP from G and PM fractions showed association with NHERF1. GFP‐NpT2a lacking the terminal – TRL motif lacked glycosylation and failed to associate with NHERF1 or traffic to the AM. Confocal imaging confirmed failure of the TRL deletion mutant to localize to the AM. We conclude that NpT2a associates with NHERF1 in the G through the C‐terminal PDZ binding domain and that this association is essential for NpT2a glycosylation and AM trafficking. Supported by VA