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The predicted collagen-binding domains of Drosophila SPARC are essential for survival and for collagen IV distribution and assembly into basement membranes.
- Source :
-
Developmental biology [Dev Biol] 2020 May 15; Vol. 461 (2), pp. 197-209. Date of Electronic Publication: 2020 Feb 20. - Publication Year :
- 2020
-
Abstract
- The assembly of basement membranes (BMs) into tissue-specific morphoregulatory structures requires non-core BM components. Work in Drosophila indicates a principal role of collagen-binding matricellular glycoprotein SPARC (Secreted Protein, Acidic, Rich in Cysteine) in larval fat body BM assembly. We report that SPARC and collagen IV (Col(IV)) first colocalize in the trans-Golgi of hemocyte-like cell lines. Mutating the collagen-binding domains of Drosophila SPARC led to the loss of colocalization with Col(IV), a fibrotic-like BM, and 2 <superscript>nd</superscript> instar larval lethality, indicating that SPARC binding to Col(IV) is essential for survival. Analysis of this mutant at 2 <superscript>nd</superscript> instar reveals increased Col(IV) puncta within adipocytes, reflecting a disruption in the intracellular chaperone-like activity of SPARC. Removal of the disulfide bridge in the C-terminal EF-hand2 of SPARC, which is known to enhance Col(IV) binding, did not lead to larval lethality; however, a less intense fat body phenotype was observed. Additionally, both SPARC mutants exhibited altered fat body BM pore topography. Wing imaginal disc-derived SPARC did not localize within Col(IV)-rich matrices. This raises the possibility that SPARC interaction with Col(IV) requires initial intracellular interaction to colocalize at the BM or that wing-derived SPARC undergoes differential post-translational modifications that impacts its function. Collectively, these data provide evidence that the chaperone-like activity of SPARC on Col(IV) begins just prior to their co-secretion and demonstrate for the first time that the Col(IV) chaperone-like activity of SPARC is necessary for Drosophila development beyond the 2 <superscript>nd</superscript> instar.<br />Competing Interests: Declaration of competing interest None.<br /> (Copyright © 2020 Elsevier Inc. All rights reserved.)
- Subjects :
- Adipocytes cytology
Animals
Animals, Genetically Modified
Binding Sites
COP-Coated Vesicles metabolism
CRISPR-Cas Systems
Cell Size
Cystine metabolism
Drosophila melanogaster growth & development
Drosophila melanogaster metabolism
Fat Body cytology
Fat Body growth & development
Genes, Lethal
Hemocytes metabolism
Larva
Osteonectin chemistry
Osteonectin deficiency
Osteonectin genetics
Protein Domains
Wings, Animal growth & development
Basement Membrane metabolism
Collagen Type IV metabolism
Drosophila Proteins physiology
Molecular Chaperones physiology
Osteonectin physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1095-564X
- Volume :
- 461
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Developmental biology
- Publication Type :
- Academic Journal
- Accession number :
- 32087195
- Full Text :
- https://doi.org/10.1016/j.ydbio.2020.02.011