Fibulin-3, -4, and -5 are highly susceptible to proteolysis, interact with cells and heparin, and form multimers

Extracellular short fibulins, fibulin-3, -4, and -5, are components of the elastic fiber/microfibril system and are implicated in the formation and homeostasis of elastic tissues. In this study, we report new structural and functional properties of the short fibulins. Full-length human short fibulins were recombinantly expressed in human embryonic kidney cells and purified by immobilized metal ion affinity chromatography. All three fibulins showed various levels of degradation after the purification procedure. N-terminal sequencing revealed that all three fibulins are highly susceptible to proteolysis within the N-terminal linker region of the first calcium-binding epidermal growth factor domain. Proteolytic susceptibility of the linker correlated with its length. Exposure of these fibulins to matrix metalloproteinase (MMP)-1, -2, -3, -7, -9, and -12 resulted in similar proteolytic fragments with MMP-7 and -12 being the most potent proteases. Fibulin-3 proteolysis was almost completely inhibited in cell culture by the addition of 25 μm doxycycline (a broad spectrum MMP inhibitor). Reducible fibulin-4 dimerization and multimerization were consistently observed by SDS-PAGE, Western blotting, and mass spectrometry. Atomic force microscopy identified monomers, dimers, and multimers in purified fibulin-4 preparations with sizes of ∼10-15, ∼20-25, and ∼30-50 nm, respectively. All short fibulins strongly adhered to human fibroblasts and smooth muscle cells. Although only fibulin-5 has an RGD integrin binding site, all short fibulins adhere at a similar level to the respective cells. Solid phase binding assays detected strong calcium-dependent binding of the short fibulins to immobilized heparin, suggesting that these fibulins may bind cell surface-located heparan sulfate.

Medienart:

E-Artikel

Erscheinungsjahr:

2013

Erschienen:

2013

Enthalten in:

Zur Gesamtaufnahme - volume:288

Enthalten in:

The Journal of biological chemistry - 288(2013), 31 vom: 02. Aug., Seite 22821-35

Sprache:

Englisch

Beteiligte Personen:

Djokic, Jelena [VerfasserIn]
Fagotto-Kaufmann, Christine [VerfasserIn]
Bartels, Rainer [VerfasserIn]
Nelea, Valentin [VerfasserIn]
Reinhardt, Dieter P [VerfasserIn]

Links:

Volltext

Themen:

9005-49-6
Biopolymers
Cell Adhesion
DNA Primers
EFEMP1 protein, human
EFEMP2 protein, human
Elastic Fiber
Extracellular Matrix
Extracellular Matrix Proteins
FBLN5 protein, human
Fibulin
Heparin
Heparin-binding Protein
Journal Article
Matrix Metalloproteinase (MMP)
Protein Multimerization
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 21.10.2013

Date Revised 21.10.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1074/jbc.M112.439158

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM228485002