--- OA_place: publisher OA_type: green _id: '22276' abstract: - lang: eng text: Tissue tension is a key determinant of tissue shape, and its regulation is essential for both morphogenesis and the maintenance of tissue integrity. During zebrafish embryogenesis, the enveloping layer (EVL) – an epithelial monolayer covering the blastoderm – undergoes extensive spreading that is driven by pulling forces exerted at its margin and more than doubles its surface area. Yet whether and how the EVL actively regulates its tissue tension during this process remains unclear. Here, we show that the EVL maintains constant tissue tension while spreading, and that it achieves this by reducing apical cell contractility in response to the same pulling forces that drive its spreading. We identify a mechanosensitive pathway underlying this response, mediated by the scaffold/adaptor protein Kibra regulating the activity of atypical protein kinase C (aPKC) at the apical domain of EVL cells. Under low mechanical stretch, Kibra forms condensates at the base of actin-based apical projections, where it activates Myosin II to increase apical contractility through aPKC downregulation. As mechanical stretch increases, apical projections disassemble, Kibra condensates dissolve, and aPKC activity rises. Elevated aPKC activity in turn reduces apical contractility by reducing Myosin II activity, thereby maintaining constant tissue tension despite increased mechanical stretch. Together, these findings reveal a mechanosensitive mechanism that enables robust adaptation of tissue tension to changing mechanical stretch, ensuring efficient tissue spreading and morphogenesis. acknowledged_ssus: - _id: Bio - _id: LifeSc - _id: EM-Fac acknowledgement: We thank all members of the Heisenberg group for discussion and feedback on the manuscript, and the Imaging and Optics Facility, the Life Science Support Facility and the Electron Microscopy Facility of the Institute of Science and Technology Austria (ISTA) for their continued support. We are grateful to M. Sonawane (Tata Institute of Fundamental Research, India) for providing the pCS2-HA-aPKC (PKCι)-V260F (DN) and pCS2-HA-aPKC (PKCι)-A122E (CA) plasmids, and to I. Mayer for the discussion. Molecular graphics and analyses were performed with UCSF ChimeraX, developed by the Resource for Biocomputing, Visualization, and Informatics at the University of California, San Francisco, with support from National Institutes of Health R01-GM129325 and the Office of Cyber Infrastructure and Computational Biology, National Institute of Allergy and Infectious Diseases. This research was funded in whole or in part by the Austrian Science Fund (FWF; grant no. PAT5044023) to C.-P.H., and by a JSPS Overseas Research Fellowship and an EMBO Postdoctoral Fellowship (ALTF 16-2022) to N.H. article_processing_charge: No author: - first_name: Naoya full_name: Hino, Naoya id: 5299a9ce-7679-11eb-a7bc-d1e62b936307 last_name: Hino - first_name: Tushna full_name: Kapoor, Tushna id: e3b3eda7-fd4d-11eb-8fd8-c40af7a478b1 last_name: Kapoor - first_name: Uday R full_name: Gubbala, Uday R id: bb4a0dc4-32c9-11ee-b5ce-a97ceedd5924 last_name: Gubbala - first_name: Edouard B full_name: Hannezo, Edouard B id: 3A9DB764-F248-11E8-B48F-1D18A9856A87 last_name: Hannezo orcid: 0000-0001-6005-1561 - first_name: Carl-Philipp J full_name: Heisenberg, Carl-Philipp J id: 39427864-F248-11E8-B48F-1D18A9856A87 last_name: Heisenberg orcid: 0000-0002-0912-4566 citation: ama: Hino N, Kapoor T, Gubbala UR, Hannezo EB, Heisenberg C-PJ. Apical domain mechanosensation regulates tissue tension homeostasis. apa: Hino, N., Kapoor, T., Gubbala, U. R., Hannezo, E. B., & Heisenberg, C.-P. J. (n.d.). Apical domain mechanosensation regulates tissue tension homeostasis. Institute of Science and Technology Austria. chicago: Hino, Naoya, Tushna Kapoor, Uday R Gubbala, Edouard B Hannezo, and Carl-Philipp J Heisenberg. “Apical Domain Mechanosensation Regulates Tissue Tension Homeostasis.” Institute of Science and Technology Austria, n.d. ieee: N. Hino, T. Kapoor, U. R. Gubbala, E. B. Hannezo, and C.-P. J. Heisenberg, “Apical domain mechanosensation regulates tissue tension homeostasis.” Institute of Science and Technology Austria. ista: Hino N, Kapoor T, Gubbala UR, Hannezo EB, Heisenberg C-PJ. Apical domain mechanosensation regulates tissue tension homeostasis. mla: Hino, Naoya, et al. Apical Domain Mechanosensation Regulates Tissue Tension Homeostasis. Institute of Science and Technology Austria. short: N. Hino, T. Kapoor, U.R. Gubbala, E.B. Hannezo, C.-P.J. Heisenberg, (n.d.). corr_author: '1' das_tickbox: '1' dataavailabilitystatement: "The MATLAB code for image analysis, and the full model code, including all parameter values\r\nand condition-specific settings, are available on GitHub at https://github.com/uday2607/EVL-tension-homeostasis.git." date_created: 2026-07-13T09:03:26Z date_published: 2026-07-14T00:00:00Z date_updated: 2026-07-14T07:07:41Z day: '14' ddc: - '570' department: - _id: CaHe - _id: EdHa - _id: GradSch file: - access_level: open_access checksum: 66444afd243dce7d383d52d44e8d34a4 content_type: application/pdf creator: nhino date_created: 2026-07-13T09:16:20Z date_updated: 2026-07-13T09:16:20Z file_id: '22283' file_name: Main_text_and_figures.pdf file_size: 12477675 relation: main_file success: 1 - access_level: open_access checksum: 90bceb34de64ec792c5de117f0890d05 content_type: application/pdf creator: nhino date_created: 2026-07-13T09:16:25Z date_updated: 2026-07-13T09:16:25Z file_id: '22284' file_name: Supplementary_figures.pdf file_size: 4545901 relation: main_file success: 1 - access_level: open_access checksum: 9d9ab89c372142f2ffb6c8c625334d7f content_type: video/mp4 creator: nhino date_created: 2026-07-13T09:16:28Z date_updated: 2026-07-13T09:16:28Z file_id: '22285' file_name: Supplementary_Video1.mp4 file_size: 10349451 relation: main_file success: 1 file_date_updated: 2026-07-13T09:16:28Z has_accepted_license: '1' keyword: - Epithelial spreading - tissue tension - mechanosensation - aPKC - Kibra - zebrafish language: - iso: eng month: '07' oa: 1 oa_version: Preprint project: - _id: 8f060199-16d5-11f0-9cad-f3253b266c46 grant_number: PAT 5044023 name: Keratins in epithelial tissue spreading - _id: 34dd7f3b-11ca-11ed-8bc3-856f2c87f5da grant_number: LTF 16-2022 name: Mechanosensitive signaling activation in the crosstalk between mechanical force and tissuefluidity publication_status: draft publisher: Institute of Science and Technology Austria related_material: record: - id: '21864' relation: earlier_version status: public researchdata_availability: yes status: public supplementarymaterial: yes title: Apical domain mechanosensation regulates tissue tension homeostasis tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: preprint user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2026' ...