---
_id: '8988'
abstract:
- lang: eng
text: The differentiation of cells depends on a precise control of their internal
organization, which is the result of a complex dynamic interplay between the cytoskeleton,
molecular motors, signaling molecules, and membranes. For example, in the developing
neuron, the protein ADAP1 (ADP-ribosylation factor GTPase-activating protein [ArfGAP]
with dual pleckstrin homology [PH] domains 1) has been suggested to control dendrite
branching by regulating the small GTPase ARF6. Together with the motor protein
KIF13B, ADAP1 is also thought to mediate delivery of the second messenger phosphatidylinositol
(3,4,5)-trisphosphate (PIP3) to the axon tip, thus contributing to PIP3 polarity.
However, what defines the function of ADAP1 and how its different roles are coordinated
are still not clear. Here, we studied ADAP1’s functions using in vitro reconstitutions.
We found that KIF13B transports ADAP1 along microtubules, but that PIP3 as well
as PI(3,4)P2 act as stop signals for this transport instead of being transported.
We also demonstrate that these phosphoinositides activate ADAP1’s enzymatic activity
to catalyze GTP hydrolysis by ARF6. Together, our results support a model for
the cellular function of ADAP1, where KIF13B transports ADAP1 until it encounters
high PIP3/PI(3,4)P2 concentrations in the plasma membrane. Here, ADAP1 disassociates
from the motor to inactivate ARF6, promoting dendrite branching.
acknowledged_ssus:
- _id: Bio
- _id: LifeSc
- _id: EM-Fac
acknowledgement: "We thank Urban Bezeljak, Natalia Baranova, Mar Lopez-Pelegrin, Catarina
Alcarva, and Victoria Faas for sharing reagents and helpful discussions. We thank
Veronika Szentirmai for help with protein purifications. We thank Carrie Bernecky,
Sascha Martens, and the M.L. lab for comments on the manuscript. We thank the bioimaging
facility, the life science facility, and Armel Nicolas from the mass spec facility
at the Institute of Science and Technology (IST) Austria for technical support.
C.D. acknowledges funding from the IST fellowship program; this work was supported
by Human Frontier Science Program Young Investigator Grant\r\nRGY0083/2016. "
article_number: e2010054118
article_processing_charge: No
article_type: original
author:
- first_name: Christian F
full_name: Düllberg, Christian F
id: 459064DC-F248-11E8-B48F-1D18A9856A87
last_name: Düllberg
orcid: 0000-0001-6335-9748
- first_name: Albert
full_name: Auer, Albert
id: 3018E8C2-F248-11E8-B48F-1D18A9856A87
last_name: Auer
orcid: 0000-0002-3580-2906
- first_name: Nikola
full_name: Canigova, Nikola
id: 3795523E-F248-11E8-B48F-1D18A9856A87
last_name: Canigova
orcid: 0000-0002-8518-5926
- first_name: Katrin
full_name: Loibl, Katrin
id: 3760F32C-F248-11E8-B48F-1D18A9856A87
last_name: Loibl
orcid: 0000-0002-2429-7668
- first_name: Martin
full_name: Loose, Martin
id: 462D4284-F248-11E8-B48F-1D18A9856A87
last_name: Loose
orcid: 0000-0001-7309-9724
citation:
ama: Düllberg CF, Auer A, Canigova N, Loibl K, Loose M. In vitro reconstitution
reveals phosphoinositides as cargo-release factors and activators of the ARF6
GAP ADAP1. PNAS. 2021;118(1). doi:10.1073/pnas.2010054118
apa: Düllberg, C. F., Auer, A., Canigova, N., Loibl, K., & Loose, M. (2021).
In vitro reconstitution reveals phosphoinositides as cargo-release factors and
activators of the ARF6 GAP ADAP1. PNAS. National Academy of Sciences. https://doi.org/10.1073/pnas.2010054118
chicago: Düllberg, Christian F, Albert Auer, Nikola Canigova, Katrin Loibl, and
Martin Loose. “In Vitro Reconstitution Reveals Phosphoinositides as Cargo-Release
Factors and Activators of the ARF6 GAP ADAP1.” PNAS. National Academy of
Sciences, 2021. https://doi.org/10.1073/pnas.2010054118.
ieee: C. F. Düllberg, A. Auer, N. Canigova, K. Loibl, and M. Loose, “In vitro reconstitution
reveals phosphoinositides as cargo-release factors and activators of the ARF6
GAP ADAP1,” PNAS, vol. 118, no. 1. National Academy of Sciences, 2021.
ista: Düllberg CF, Auer A, Canigova N, Loibl K, Loose M. 2021. In vitro reconstitution
reveals phosphoinositides as cargo-release factors and activators of the ARF6
GAP ADAP1. PNAS. 118(1), e2010054118.
mla: Düllberg, Christian F., et al. “In Vitro Reconstitution Reveals Phosphoinositides
as Cargo-Release Factors and Activators of the ARF6 GAP ADAP1.” PNAS, vol.
118, no. 1, e2010054118, National Academy of Sciences, 2021, doi:10.1073/pnas.2010054118.
short: C.F. Düllberg, A. Auer, N. Canigova, K. Loibl, M. Loose, PNAS 118 (2021).
date_created: 2021-01-03T23:01:23Z
date_published: 2021-01-05T00:00:00Z
date_updated: 2023-08-04T11:20:46Z
day: '05'
department:
- _id: MaLo
- _id: MiSi
doi: 10.1073/pnas.2010054118
external_id:
isi:
- '000607270100018'
pmid:
- '33443153'
intvolume: ' 118'
isi: 1
issue: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1073/pnas.2010054118
month: '01'
oa: 1
oa_version: Published Version
pmid: 1
project:
- _id: 2599F062-B435-11E9-9278-68D0E5697425
grant_number: RGY0083/2016
name: Reconstitution of cell polarity and axis determination in a cell-free system
publication: PNAS
publication_identifier:
eissn:
- '10916490'
issn:
- '00278424'
publication_status: published
publisher: National Academy of Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: In vitro reconstitution reveals phosphoinositides as cargo-release factors
and activators of the ARF6 GAP ADAP1
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 118
year: '2021'
...
---
_id: '7580'
abstract:
- lang: eng
text: The eukaryotic endomembrane system is controlled by small GTPases of the Rab
family, which are activated at defined times and locations in a switch-like manner.
While this switch is well understood for an individual protein, how regulatory
networks produce intracellular activity patterns is currently not known. Here,
we combine in vitro reconstitution experiments with computational modeling to
study a minimal Rab5 activation network. We find that the molecular interactions
in this system give rise to a positive feedback and bistable collective switching
of Rab5. Furthermore, we find that switching near the critical point is intrinsically
stochastic and provide evidence that controlling the inactive population of Rab5
on the membrane can shape the network response. Notably, we demonstrate that collective
switching can spread on the membrane surface as a traveling wave of Rab5 activation.
Together, our findings reveal how biochemical signaling networks control vesicle
trafficking pathways and how their nonequilibrium properties define the spatiotemporal
organization of the cell.
acknowledged_ssus:
- _id: Bio
- _id: LifeSc
article_processing_charge: No
article_type: original
author:
- first_name: Urban
full_name: Bezeljak, Urban
id: 2A58201A-F248-11E8-B48F-1D18A9856A87
last_name: Bezeljak
orcid: 0000-0003-1365-5631
- first_name: Hrushikesh
full_name: Loya, Hrushikesh
last_name: Loya
- first_name: Beata M
full_name: Kaczmarek, Beata M
id: 36FA4AFA-F248-11E8-B48F-1D18A9856A87
last_name: Kaczmarek
- first_name: Timothy E.
full_name: Saunders, Timothy E.
last_name: Saunders
- first_name: Martin
full_name: Loose, Martin
id: 462D4284-F248-11E8-B48F-1D18A9856A87
last_name: Loose
orcid: 0000-0001-7309-9724
citation:
ama: Bezeljak U, Loya H, Kaczmarek BM, Saunders TE, Loose M. Stochastic activation
and bistability in a Rab GTPase regulatory network. Proceedings of the National
Academy of Sciences. 2020;117(12):6504-6549. doi:10.1073/pnas.1921027117
apa: Bezeljak, U., Loya, H., Kaczmarek, B. M., Saunders, T. E., & Loose, M.
(2020). Stochastic activation and bistability in a Rab GTPase regulatory network.
Proceedings of the National Academy of Sciences. Proceedings of the National
Academy of Sciences. https://doi.org/10.1073/pnas.1921027117
chicago: Bezeljak, Urban, Hrushikesh Loya, Beata M Kaczmarek, Timothy E. Saunders,
and Martin Loose. “Stochastic Activation and Bistability in a Rab GTPase Regulatory
Network.” Proceedings of the National Academy of Sciences. Proceedings
of the National Academy of Sciences, 2020. https://doi.org/10.1073/pnas.1921027117.
ieee: U. Bezeljak, H. Loya, B. M. Kaczmarek, T. E. Saunders, and M. Loose, “Stochastic
activation and bistability in a Rab GTPase regulatory network,” Proceedings
of the National Academy of Sciences, vol. 117, no. 12. Proceedings of the
National Academy of Sciences, pp. 6504–6549, 2020.
ista: Bezeljak U, Loya H, Kaczmarek BM, Saunders TE, Loose M. 2020. Stochastic activation
and bistability in a Rab GTPase regulatory network. Proceedings of the National
Academy of Sciences. 117(12), 6504–6549.
mla: Bezeljak, Urban, et al. “Stochastic Activation and Bistability in a Rab GTPase
Regulatory Network.” Proceedings of the National Academy of Sciences, vol.
117, no. 12, Proceedings of the National Academy of Sciences, 2020, pp. 6504–49,
doi:10.1073/pnas.1921027117.
short: U. Bezeljak, H. Loya, B.M. Kaczmarek, T.E. Saunders, M. Loose, Proceedings
of the National Academy of Sciences 117 (2020) 6504–6549.
date_created: 2020-03-12T05:32:26Z
date_published: 2020-03-24T00:00:00Z
date_updated: 2023-09-07T13:17:06Z
day: '24'
department:
- _id: MaLo
- _id: CaBe
doi: 10.1073/pnas.1921027117
external_id:
isi:
- '000521821800040'
intvolume: ' 117'
isi: 1
issue: '12'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1101/776567
month: '03'
oa: 1
oa_version: Preprint
page: 6504-6549
project:
- _id: 2599F062-B435-11E9-9278-68D0E5697425
grant_number: RGY0083/2016
name: Reconstitution of cell polarity and axis determination in a cell-free system
publication: Proceedings of the National Academy of Sciences
publication_identifier:
eissn:
- 1091-6490
issn:
- 0027-8424
publication_status: published
publisher: Proceedings of the National Academy of Sciences
quality_controlled: '1'
related_material:
link:
- description: News on IST Homepage
relation: press_release
url: https://ist.ac.at/en/news/proteins-as-molecular-switches/
record:
- id: '8341'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Stochastic activation and bistability in a Rab GTPase regulatory network
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 117
year: '2020'
...