Inhibition of Phosphatase Activity Follows Decline in Sulfatase Activity and Leads to Transcriptional Effects through Sustained Phosphorylation of Transcription Factor MITF.

Arylsulfatase B (B-acetylgalactosamine 4-sulfatase; ARSB) is the enzyme that removes 4-sulfate groups from the non-reducing end of the glycosaminoglycans chondroitin 4-sulfate and dermatan sulfate. Decline in ARSB has been shown in malignant prostate, colonic, and mammary cells and tissues, and decl...

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Main Authors: Sumit Bhattacharyya, Leo Feferman, Joanne K Tobacman
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2016-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0153463&type=printable
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author Sumit Bhattacharyya
Leo Feferman
Joanne K Tobacman
author_facet Sumit Bhattacharyya
Leo Feferman
Joanne K Tobacman
author_sort Sumit Bhattacharyya
collection DOAJ
description Arylsulfatase B (B-acetylgalactosamine 4-sulfatase; ARSB) is the enzyme that removes 4-sulfate groups from the non-reducing end of the glycosaminoglycans chondroitin 4-sulfate and dermatan sulfate. Decline in ARSB has been shown in malignant prostate, colonic, and mammary cells and tissues, and decline in ARSB leads to transcriptional events mediated by galectin-3 with AP-1 and Sp1. Increased mRNA expression of GPNMB (transmembrane glycoprotein NMB) in HepG2 cells and in hepatic tissue from ARSB-deficient mice followed decline in expression of ARSB and was mediated by the microphthalmia-associated transcription factor (MITF), but was unaffected by silencing galectin-3. Since GPNMB is increased in multiple malignancies, studies were performed to determine how decline in ARSB increased GPNMB expression. The mechanism by which decline in ARSB increased nuclear phospho-MITF was due to reduced activity of SHP2, a protein tyrosine phosphatase with Src homology (SH2) domains that regulates multiple cellular processes. SHP2 activity declined due to increased binding with chondroitin 4-sulfate when ARSB was reduced. When SHP2 activity was inhibited, phosphorylations of p38 mitogen-associated phosphokinase (MAPK) and of MITF increased, leading to GPNMB promoter activation. A dominant negative SHP2 construct, the SHP2 inhibitor PHSP1, and silencing of ARSB increased phospho-p38, nuclear MITF, and GPNMB. In contrast, constitutively active SHP2 and overexpression of ARSB inhibited GPNMB expression. The interaction between chondroitin 4-sulfate and SHP2 is a novel intersection between sulfation and phosphorylation, by which decline in ARSB and increased chondroitin 4-sulfation can inhibit SHP2, thereby regulating downstream tyrosine phosphorylations by sustained phosphorylations with associated activation of signaling and transcriptional events.
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spelling doaj-art-d97dfd5647af4ecdb592161536dc17b52025-08-20T02:39:47ZengPublic Library of Science (PLoS)PLoS ONE1932-62032016-01-01114e015346310.1371/journal.pone.0153463Inhibition of Phosphatase Activity Follows Decline in Sulfatase Activity and Leads to Transcriptional Effects through Sustained Phosphorylation of Transcription Factor MITF.Sumit BhattacharyyaLeo FefermanJoanne K TobacmanArylsulfatase B (B-acetylgalactosamine 4-sulfatase; ARSB) is the enzyme that removes 4-sulfate groups from the non-reducing end of the glycosaminoglycans chondroitin 4-sulfate and dermatan sulfate. Decline in ARSB has been shown in malignant prostate, colonic, and mammary cells and tissues, and decline in ARSB leads to transcriptional events mediated by galectin-3 with AP-1 and Sp1. Increased mRNA expression of GPNMB (transmembrane glycoprotein NMB) in HepG2 cells and in hepatic tissue from ARSB-deficient mice followed decline in expression of ARSB and was mediated by the microphthalmia-associated transcription factor (MITF), but was unaffected by silencing galectin-3. Since GPNMB is increased in multiple malignancies, studies were performed to determine how decline in ARSB increased GPNMB expression. The mechanism by which decline in ARSB increased nuclear phospho-MITF was due to reduced activity of SHP2, a protein tyrosine phosphatase with Src homology (SH2) domains that regulates multiple cellular processes. SHP2 activity declined due to increased binding with chondroitin 4-sulfate when ARSB was reduced. When SHP2 activity was inhibited, phosphorylations of p38 mitogen-associated phosphokinase (MAPK) and of MITF increased, leading to GPNMB promoter activation. A dominant negative SHP2 construct, the SHP2 inhibitor PHSP1, and silencing of ARSB increased phospho-p38, nuclear MITF, and GPNMB. In contrast, constitutively active SHP2 and overexpression of ARSB inhibited GPNMB expression. The interaction between chondroitin 4-sulfate and SHP2 is a novel intersection between sulfation and phosphorylation, by which decline in ARSB and increased chondroitin 4-sulfation can inhibit SHP2, thereby regulating downstream tyrosine phosphorylations by sustained phosphorylations with associated activation of signaling and transcriptional events.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0153463&type=printable
spellingShingle Sumit Bhattacharyya
Leo Feferman
Joanne K Tobacman
Inhibition of Phosphatase Activity Follows Decline in Sulfatase Activity and Leads to Transcriptional Effects through Sustained Phosphorylation of Transcription Factor MITF.
PLoS ONE
title Inhibition of Phosphatase Activity Follows Decline in Sulfatase Activity and Leads to Transcriptional Effects through Sustained Phosphorylation of Transcription Factor MITF.
title_full Inhibition of Phosphatase Activity Follows Decline in Sulfatase Activity and Leads to Transcriptional Effects through Sustained Phosphorylation of Transcription Factor MITF.
title_fullStr Inhibition of Phosphatase Activity Follows Decline in Sulfatase Activity and Leads to Transcriptional Effects through Sustained Phosphorylation of Transcription Factor MITF.
title_full_unstemmed Inhibition of Phosphatase Activity Follows Decline in Sulfatase Activity and Leads to Transcriptional Effects through Sustained Phosphorylation of Transcription Factor MITF.
title_short Inhibition of Phosphatase Activity Follows Decline in Sulfatase Activity and Leads to Transcriptional Effects through Sustained Phosphorylation of Transcription Factor MITF.
title_sort inhibition of phosphatase activity follows decline in sulfatase activity and leads to transcriptional effects through sustained phosphorylation of transcription factor mitf
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0153463&type=printable
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