title: Alterations in the proteome of the NHERF2 knockout mouse jejunal brush border membrane vesicles.
abstract: To identify additional potential functions for the multi-PDZ domain containing protein Na+/H+ exchanger regulatory factor 2 (NHERF2), which is present in the apical domain of intestinal epithelial cells, proteomic studies of mouse jejunal villus epithelial cell brush border membrane vesicles compared wild-type to homozygous NHERF2 knockout FVB mice by a two-dimensional liquid chromatography-tandem mass spectrometry (LC-MS/MS)-iTRAQ approach. Jejunal architecture appeared normal in NHERF2 null in terms of villus length and crypt depth, Paneth cell number, and microvillus structure by electron microscopy. There was also no change in proliferative activity based on BrdU labeling. Four brush border membrane vesicles (BBMV) preparations from wild-type mouse jejunum were compared with four preparations from NHERF2 knockout mice. LC-MS/MS identified 450 proteins in both matched wild-type and NHERF2 null BBMV; 13 proteins were changed in two or more separate BBMV preparations (9 increased and 4 decreased in NHERF2 null mice), while an additional 92 proteins were changed in a single BBMV preparation (68 increased and 24 decreased in NHERF2 null mice). These proteins were categorized as 1) transport proteins (one increased and two decreased in NHERF2 null); 2) signaling molecules (2 increased in NHERF2 null); 3) cytoskeleton/junctional proteins (4 upregulated and 1 downregulated in NHERF2 null); and 4) metabolic proteins/intrinsic BB proteins) (2 upregulated and 1 downregulated in NHERF2 null). Immunoblotting of BBMV was used to validate or extend the findings, demonstrating increase in BBMV of NHERF2 null of MCT1, coronin 3, and ezrin. The proteome of the NHERF2 null mouse small intestinal BB demonstrates up- and downregulation of multiple transport proteins, signaling molecules, cytoskeletal proteins, tight junctional and adherens junction proteins, and proteins involved in metabolism, suggesting involvement of NHERF2 in multiple apical regulatory processes and interactions with luminal contents.
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2195, USA. mdonowit@jhmi.edu
authors.forename: M
authors.initials: M
authors.lastname: Donowitz
authors.forename: S
authors.initials: S
authors.lastname: Singh
authors.forename: P
authors.initials: P
authors.lastname: Singh
authors.forename: M
authors.initials: M
authors.lastname: Chakraborty
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: R
authors.initials: R
authors.lastname: Murtazina
authors.forename: M
authors.initials: M
authors.lastname: Gucek
authors.forename: R N
authors.initials: RN
authors.lastname: Cole
authors.forename: N C
authors.initials: NC
authors.lastname: Zachos
authors.forename: F F
authors.initials: FF
authors.lastname: Salahuddin
authors.forename: O
authors.initials: O
authors.lastname: Kovbasnjuk
authors.forename: N
authors.initials: N
authors.lastname: Broere
authors.forename: W G
authors.initials: WG
authors.lastname: Smalley-Freed
authors.forename: A B
authors.initials: AB
authors.lastname: Reynolds
authors.forename: A L
authors.initials: AL
authors.lastname: Hubbard
authors.forename: U
authors.initials: U
authors.lastname: Seidler
authors.forename: E
authors.initials: E
authors.lastname: Weinman
authors.forename: H R
authors.initials: HR
authors.lastname: de Jonge
authors.forename: B M
authors.initials: BM
authors.lastname: Hogema
authors.forename: X
authors.initials: X
authors.lastname: Li
mesh_terms: D000818:Animals; D015820:Cadherins / Q000378:metabolism; D049109:Cell Proliferation; D002853:Chromatography, Liquid; D003599:Cytoskeleton / Q000378:metabolism; D015536:Down-Regulation; D005455:Fluorescent Antibody Technique; D007583:Jejunum / Q000378:metabolism*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008871:Microvilli / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D020543:Proteome / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics* / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
chemical_list: D015820:Cadherins; D010750:Phosphoproteins; D020543:Proteome; D017923:Sodium-Hydrogen Exchangers; D051176:beta Catenin; C093376:sodium-hydrogen exchanger regulatory factor