Scavenger receptor endocytosis controls apical membrane morphogenesis in the Drosophila airways

Abstract
Data availability
Article and author information
Metrics

Abstract

The acquisition of distinct branch sizes and shapes is a central aspect in tubular organ morphogenesis and function. In the Drosophila airway tree, the interplay of apical ECM components with the underlying membrane and cytoskeleton controls tube elongation, but the link between ECM composition with apical membrane morphogenesis and tube size regulation is elusive. Here, we characterized Emp (epithelial membrane protein), a Drosophila CD36-homologue belonging to the scavenger receptor class B protein-family. emp mutant embryos fail to internalize the luminal chitin deacetylases Serp and Verm at the final stages of airway maturation and die at hatching with liquid filled airways. Emp localizes in apical epithelial membranes and shows cargo selectivity for LDLr-domain containing proteins. emp mutants also display over elongated tracheal tubes with increased levels of the apical proteins Crb, DE-cad and phosphorylated Src (p-Src). We show that Emp associates with and organizes the βH-Spectrin cytoskeleton and is itself confined by apical F-actin bundles. Overexpression or loss of its cargo protein Serp lead to abnormal apical accumulations of Emp and perturbations in p-Src levels. We propose that during morphogenesis, Emp senses and responds to luminal cargo levels by initiating apical membrane endocytosis along the longitudinal tube axis and thereby restricts airway elongation.

Data availability

All data generated or analyzed during this study are included in the manuscript and supporting files. Unprocessed Western blots are provided as source data files in zip format.

Article and author information

Author details

Ana Sofia Pinheiro

Department of Molecular Biosciences, Stockholm University, Stockholm, Sweden

Competing interests
The authors declare that no competing interests exist.
Vasilios Tsarouhas

Department of Molecular Biosciences, Stockholm University, Stockholm, Sweden

For correspondence
Vasilios.Tsarouhas@su.se

Competing interests
The authors declare that no competing interests exist.
Kirsten André Senti

Institute of Molecular Biotechnology, Vienna, Austria

Competing interests
The authors declare that no competing interests exist.
Badrul Arefin

Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0003-1117-9125
Christos Samakovlis

Department of Molecular Biosciences, Stockholm University, Stockholm, Sweden

For correspondence
christos.samakovlis@scilifelab.se

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-9153-6040

Funding

Vetenskapsrådet

Christos Samakovlis

Cancerfonden

Christos Samakovlis

O. E. och Edla Johanssons Vetenskapliga Stiftelse

Vasilios Tsarouhas

Magnus Bergvalls Stiftelse (2021-04453)

Vasilios Tsarouhas

Deutsche Forschungsgemeinschaft (KFO309)

Christos Samakovlis

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.