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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Cholesterol Regulates the Incorporation and Catalytic Activity of Tissue-Nonspecific Alkaline Phosphatase in DPPC Monolayers

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Author(s):
Derradi, R. [1] ; Bolean, M. [1] ; Simao, A. M. S. [1] ; Caseli, L. [2] ; Millan, J. L. [3] ; Bottini, M. [3, 4] ; Ciancaglini, P. [1] ; Ramos, A. P. [1]
Total Authors: 8
Affiliation:
[1] Univ Sao Paulo, Dept Chem, Fac Philosophy Sci & Letters Ribeirao Preto, Dept Chem, Ave Bandeirantes 3900, BR-14040901 Ribeirao Preto, SP - Brazil
[2] Univ Fed Sao Paulo, Inst Environm Chem & Pharmaceut Sci, Rua Sao Nicolau, 210 Ctr, BR-09913030 Diadema, SP - Brazil
[3] Sanford Burnham Prebys Med Discovery Inst, La Jolla, CA 92037 - USA
[4] Univ Roma Tor Vergata, Dept Expt Med, I-00133 Rome - Italy
Total Affiliations: 4
Document type: Journal article
Source: Langmuir; v. 35, n. 47, p. 15232-15241, NOV 26 2019.
Web of Science Citations: 0
Abstract

Matrix vesicles (MVs) are a special class of extracellular vesicles that drive bone and dentin mineralization by providing the essential enzymes and ions for the nucleation and propagation of mineral crystals. Tissue-nonspecific alkaline phosphatase (TNAP) is an integral protein of MV membrane and participates in biomineralization by hydrolyzing extracellular pyrophosphate (PPi), a strong mineralization inhibitor, and forming inorganic phosphate (P-i), necessary for the growth of mineral crystals inside MVs and their propagation once released in the extracellular matrix. MV membrane is enriched in cholesterol (CHOL), which influences the incorporation and activity of integral proteins in biologic membranes; however, how CHOL controls the incorporation and activity of TNAP in MV membrane has not yet been elucidated. In the present study, Langmuir monolayers were used as a MV membrane biomimetic model to assess how CHOL affects TNAP incorporation and activity. Surface pressure-area (pi-A) isotherms of binary dipalmitoilphosphatidylcholine (DPPC)/CHOL monolayers showed that TNAP incorporation increases with CHOL concentration. Infrared spectroscopy showed that CHOL influences the conformation and orientation of the enzyme. Optical-fluorescence micrographs of the monolayers revealed the tendency of TNAP to incorporate into CHOL-rich microdomains. These data suggest that TNAP penetrates more efficiently and occupies a higher surface area into monolayers with a lower CHOL concentration due to the higher membrane fluidity. However, the quantity of enzyme transferred to solid supports as well as the enzymatic activity were higher using monolayers with a higher CHOL concentration due to increased rigidity that changes the enzyme orientation at the air-solid interface. These data provide new insights regarding the interfacial behavior of TNAP and CHOL in MVs and shed light on the biochemical and biophysical processes occurring in the MV membrane during biomineralization at the molecular level. (AU)

FAPESP's process: 17/08892-9 - Bioactive surfaces designed from Langmuir-Blodgett Films and Biominerals
Grantee:Ana Paula Ramos
Support Opportunities: Regular Research Grants
FAPESP's process: 15/03594-4 - Adsorption study of alkaline phosphatase in Langmuir monolayers containing cholesterol-rich lipidic microdomains
Grantee:Rafael Derradi
Support Opportunities: Scholarships in Brazil - Master
FAPESP's process: 14/11941-3 - Are collagen and Annexin V responsible for the control in the biomineralization process?
Grantee:Pietro Ciancaglini
Support Opportunities: Regular Research Grants
FAPESP's process: 16/21236-0 - Extracellular matrix vesicles (MVs) mimetic systems to study the regulation of the biomineralization process: proteoliposomes containing NPP1 and Annexin V
Grantee:Pietro Ciancaglini
Support Opportunities: Regular Research Grants