| Disulfide bonds are critical for tissue-nonspecific alkaline phosphatase function revealed by analysis of mutant proteins bearing a C(201)-Y or C(489)-S substitution associated with severe hypophosphatasia. | |
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MedLine Citation:
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PMID: 22266140 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Hypophosphatasia (HPP), a rare genetic disease characterized by reduced serum alkaline phosphatase (ALP) activity and failure in bone and tooth mineralization, is caused by mutations in tissue-nonspecific ALP (TNSALP) gene. Two missense mutations (C201Y and C489S, standardized nomenclature) of TNSALP, involved in intra-chain disulfide bonds, were reported in patients diagnosed with perinatal HPP (Taillandier A. et al. Hum. Mutat. 13 (1999) 171-172, Hum. Mutat. 15 (2000) 293). To investigate the role of the disulfide bond in TNSALP, we expressed TNSALP (C201Y) and TNSALP (C489S) in COS-1 cells transiently. Compared with the wild-type enzyme [TNSALP (W)], both the TNSALP mutants exhibited a diminished ALP activity in the cells, where a 66kDa immature form was predominant with a marginal amount of a 80kDa mature form of TNSALP. Detailed studies on Tet-On CHO established cell line expressing TNSALP (W) or TNSALP (C201Y) showed that the 66kDa form of TNSALP (C201Y) exists as a monomer in contrast to a dimer of TNSALP (W). Only a small fraction of the TNSALP (C201Y) reached cell surface as the 80kDa mature form, though most of the 66kDa form was found to be endo-β-N-acetylglucosaminidase H sensitive and rapidly degraded in proteasome following polyubiquitination. Collectively, these results indicate not only that the intra-subunit disulfide bonds are crucial for TNSALP to properly fold and assemble into the dimeric enzyme, but also that the development of HPP associated with TNSALP (C201Y) or TNSALP (C489S) is attributed to decreased cell surface appearance of the functional enzyme. |
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Authors:
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Yasuhito Satou; Hiba A Al-Shawahi; Sara Sultana; Saori Makita; Miwa Sohda; Kimimitsu Oda |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-1-14 |
Journal Detail:
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Title: Biochimica et biophysica acta Volume: - ISSN: 0006-3002 ISO Abbreviation: - Publication Date: 2012 Jan |
Date Detail:
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Created Date: 2012-1-23 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0217513 Medline TA: Biochim Biophys Acta Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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Copyright © 2012. Published by Elsevier B.V. |
Affiliation:
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Division of Oral Biochemistry, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Chuo-ku, Niigata 951-8514, Japan. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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