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Updated: Jun 26, 2026

Using Microfluidics and Fluorescence Microscopy to Study the Assembly Dynamics of Single Actin Filaments and Bundles
Published on: May 5, 2022
DANCE/fibulin-5 promotes elastic fiber formation in a tropoelastin isoform-dependent manner
Risa Nonaka1, Satoshi Onoue, Hiroshi Wachi
1Department of Clinical Chemistry, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan.
Objective:
To investigate a function of fibulin-5 in the elastic fiber formation, we studied the molecular interactions among elastin, fibrillin-1, and fibulin-5 in the extracellular space and the maturation of tropoelastin using retinal pigment epithelial cells (ARPE-19).
Design And Methods:
Bacterial recombinant tropoelastin (rTE) was added to ARPE-19 cells overexpressing V5-tagged fibulin-5 (ARPE-Fibulin-5). These elastic fibers were evaluated by immunofluorescence staining, the quantitative analysis of cross-linked amino acids, and semi-quantitative analysis of matrix-associated tropoelastin.
Results:
Immunoprecipitation assays revealed that fibulin-5 is able to separately interact with tropoelastin or fibrillin-1 in the culture medium. Moreover, immunofluorescent staining showed that elastin, fibrillin-1, and fibulin-5 co-localize in the extracellular matrix. Desmosine levels were significantly increased in ARPE-Fibulin-5 relative to untransfected cells in spite of equal deposition of tropoelastin by enzyme-linked immunosorbent assay. The addition of a tropoelastin isoform, which lacked the peptide encoded by exon 26A (Delta26A) and could bind to fibulin-5 strongly, led to a larger increase in cross-linking amino acids compared to tropoelastin containing the exon 26A peptide sequence.
Conclusion:
These data provide new insights into the initial steps of elastic fiber assembly and identify fibulin-5 and tropoelastin isoforms as potential targets for the regeneration of elastic fibers in vivo.
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