Cell Ratcheting Through the Sbf RabGEF Directs Force Balancing and Stepped Apical Constriction

Publication Date

9-27-2019

Document Type

Article

Organizational Units

College of Natural Science and Mathematics, Biological Sciences, Physics and Astronomy

Keywords

Cytoskeleton, Development, Trafficking, Cell ratcheting, Sbf RabGEF, Apical constriction

Abstract

During Drosophila melanogaster gastrulation, the invagination of the prospective mesoderm is driven by the pulsed constriction of apical surfaces. Here, we address the mechanisms by which the irreversibility of pulsed events is achieved while also permitting uniform epithelial behaviors to emerge. We use MSD-based analyses to identify contractile steps and find that when a trafficking pathway initiated by Sbf is disrupted, contractile steps become reversible. Sbf localizes to tubular, apical surfaces and associates with Rab35, where it promotes Rab GTP exchange. Interestingly, when Sbf/Rab35 function is compromised, the apical plasma membrane becomes deeply convoluted, and nonuniform cell behaviors begin to emerge. Consistent with this, Sbf/Rab35 appears to prefigure and organize the apical surface for efficient Myosin function. Finally, we show that Sbf/Rab35/CME directs the plasma membrane to Rab11 endosomes through a dynamic interaction with Rab5 endosomes. These results suggest that periodic ratcheting events shift excess membrane from cell apices into endosomal pathways to permit reshaping of actomyosin networks and the apical surface.

Copyright Date

9-27-2019

Copyright Statement / License for Reuse

This work is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 International License.

Rights Holder

The Authors

Provenance

Received from author

File Format

application/pdf

Language

English (eng)

Extent

16 pgs

File Size

5133 KB

Publication Statement

Copyright is held by the authors. User is responsible for all copyright compliance. This article was originally published as:

Miao, H., Vanderleest, T., E., Jewett, C. E., Loerke, D., & Blankenship, J. T. (2019). Cell ratcheting through the Sbf RabGEF directs force balancing and stepped apical constriction. Journal of Cell Biology, 218(11), 3845–3860. DOI: 10.1083/jcb.201905082

Publication Title

Journal of Cell Biology

Volume

218

Issue

11

First Page

3845

Last Page

3860

ISSN

1540-8140

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