Menu

Close

S-acylated Golga7b stabilises DHHC5 at the plasma membrane to regulate desmosome assembly and cell adhesion.

Keith T Woodley, Mark O Collins

Preprint posted on December 06, 2018 https://www.biorxiv.org/content/early/2018/12/06/481861

Let’s stick together! Regulation of cell adhesion by biology’s next top post-translational modification, palmitoylation!

Selected by Abagael Lasseigne

Categories: biochemistry, cell biology

Background:

Palmitoylation is a reversible, post-translational modification where a lipid is attached to cysteine residues to increase the hydrophobicity of a protein. Little is know about the regulation of palmitoyl acyltransferases (PATs), which attach these lipids via their catalytic site. DHHC5 is a human PAT, with palmitoylation sites of its own, that localizes to the plasma membrane and is known to be involved in tumor growth, massive palmitoylation-dependent endocytosis in the heart, and synaptic plasticity. Up until now, it was unclear how DHHC5 was regulated and what precise molecular roles it might be playing.

Key findings:

This paper identified another protein, Golga7b, that interacts with DHHC5 and is required for its membrane localization in a palmitoylation-dependent manner. When expressed alone in cell culture, DHHC5 localizes to the cytoplasm. However, in the presence of Golga7b, it localizes to the plasma membrane but only if Golga7b can be palmitoylated. This suggests that Golga7b palmitoylation may be initiating the formation of a complex with DHHC5 at the cell membrane. The authors next wanted to understand how this complex might be functioning, so, utilizing mass spectrometry, they identified proteins that interacted strongly with the membrane form of DHHC5. Membrane DHHC5 interacted with more proteins overall than the cytoplasmic form, especially those involved in cell adhesion. The authors then showed that cell adhesion is reduced in cells depleted of DHHC5. Finally, the authors showed that a cadherin, desmogelin-2, found to interact with and be palmitoylated by DHHC5, is removed from cell adhesions in the absence of either DHHC5 or Golga7b. This suggests an overall model where a Golga7b/DHHC5 complex, regulated by palmitoylation, may be localizing to the membrane and palmitoylating the appropriate adhesion proteins (such as desmogelin-2) therefore facilitating cell to cell adhesion.

Why I like this preprint:

These results suggest that DHHC5 may be the PAT that is responsible for palmitoylating membrane proteins involved in cell adhesion. I like this preprint because:

1) I study electrical synapses which are a form of gap junction. Cell adhesion at electrical synapses is still poorly understood, but papers such as this that elucidate the regulators of cell adhesion inform my work on how electrical synapses could be developing; and

2) More research is showing the importance of palmitoylation as a post-translational modification. Specifically in neuroscience, palmitoylation of synaptic scaffolding proteins regulates chemical synapse formation and plasticity. Therefore, it is important for us to understand the regulation of PATs responsible for palmitoylation in different circumstances.

Future directions:

The primary future directions are to identify other adhesion proteins interacting with this complex and to test this overall model in vivo.

Questions for the author:

  • Is the interaction between Golga7b and DHHC5 direct?
  • Is this interaction the same in different cell types?
  • DHHC5 can also be phosphorylated. How might this fit into the model?
  • Does DHHC5’s potential role in cell adhesion explain its prior described functions in tumors, cardiac tissue, and the nervous system?
  • Do you have any predictions regarding how/if this process might occur in vivo?
    • Is DHHC5 actually palmitoylating Golga7b in an animal?
    • Can this complex be visualized?
    • Does Golga7b palmitoylation target DHHC5 to the cell membrane in vivo?

Tags: cell adhesion, desmosome, dhhc5, golga7b, palmitoylation, post-translational modification, protein s- acyltransferase

Posted on: 28th January 2019 , updated on: 29th January 2019

Read preprint (No Ratings Yet)




  • Author's response

    Keith Woodley and Mark Collins shared

    Dear Abagael

    Thank you for your interest in our paper.

    Is the interaction between Golga7b direct?

    The interaction between Golga7b and DHHC5 is likely to be direct, but this is unconfirmed. DHHC5 and Golga7b co-immunoprecipitate and this interaction isabolished upon mutation of palmitoylation sites in the C-terminus of DHHC5. Therefore, we can say that they can form a complex that is regulated by structural features in the C-terminus of DHHC5. Another technique such as cross-linking-Mass Spectrometry would confirm that the interaction is direct and would have the added benefit of allowing the interaction site(s) to be mapped.

    Is this interaction the same in different cell types?

    The interaction appears to be the same in a number of cell types. Pulldowns have been performed in HEK293 and HeLa cell lines and with endogenous proteins from mouse forebrain lysates, so the interaction certainly seems to be the same in multiple cell types and the effects of Golga7b on DHHC5 are the same in all the cell lines mentioned.

    DHHC5 can also phosphorylate proteins. How might this fit into the model?

    The Bamji lab hasshown that DHHC5 can be phosphorylated by Fyn kinase in neurons and the function of this phosphorylation is to stabilise DHHC5 with PSD-95 at the postsynaptic membrane. Neuronal activity disrupts the interaction between DHHC5 and Fyn and leads to the endocytosis of DHHC5. This activity dependent movement of DHHC5 allows it to then palmitoylate another substrate (δ-catenin) in the dendritic shaft which then leads to changes in synaptic structure and glutamate receptor stabilisation in the postsynaptic membrane. Just how this phosphorylation-dependent cycling of DHHC5 at synapses integrates with our model of how DHHC5 plasma membrane localisation is regulated by Golga7b binding and palmitoylation, remains to be resolved. Given that we can detect a robust interaction between DHHC5 and Golga7b in brain lysates, this would suggest that it may also regulate DHHC5 localisation at synapses. If this is the case, it is likely that phosphorylation and palmitoylation could work in concert to modulate the endocytosis of DHHC5.

    It is also worth pointing out that DHHC5 is heavily modified by phosphorylation as well as other PTMs (at over 100 sites, https://www.phosphosite.org/proteinAction?id=5460) such as acetylation and ubiquitination. Many of these PTM sites are located on the particularly long cytoplasmic domain of DHHC5 and may contribute to the regulation of DHHC5 activity, localisation and substrate specificity.

    Does DHHC5’s potential role in cell adhesion explain its prior described functions in tumors, cardiac tissue, and the nervous system?

    The effects of DHHC5 on adhesion could go some way to explaining the role of DHHC5 in neurons, as it could regulate adhesion at synapses. In tumours, the loss of adhesion would likely lead to epithelial to mesenchymal transition and subsequent metastasis, but this role hasn’t been assigned to DHHC5 in the past. DHHC5 regulates a number of process in the heart such as massive endocytosis (MEND) and the cardiac sodium pump but a specific role of DHHC5 in the regulation of adhesion in the heart has not been reported.

    Do you have any predictions regarding how/if this process might occur in vivo?

    It is likely that DHHC5 is the major Golga7b palmitoylating enzyme in vivo although a knockout animal would need to be generated to confirm this. No full knockout has been generated to our knowledge, and this could prove difficult as DHHC5 does seem to have a hand in many important processes so a knockout could be embryonically lethal. A gene trap mouse that had 5% of endogenous expression showed a 50% embryonic lethality in mice. Our data suggestthat DHHC5 is targeted to the plasma membrane without Golga7b, but that Golga7b is needed to stabilise it there, but this process could be cell type specific. It is possible that there are other factors in vivoor in other cell types that could contribute to the localisation of DHHC5 at the plasma membrane. For example, loss of DHHC5 phosphorylation promotes endocytosis in neurons, so unless this process involves a cascade that results in the loss of Golga7b palmitoylation, this event could be the main determinant of DHHC5 endocytosis in this cell type.

    Thank you again for your interest, hopefully,we’ve answered your questions and that this work will lead to a greater understanding of DHHC5 and how it acts in different cell types and tissues.

    Keith and Mark

    2 comments

    3 weeks

    Dale Martin

    Dear Abigail, I liked your take on this paper. If you are interested in palmitoylation at the synapse, then you might like this paper too, where we looked at what pathways and diseases palmitoylation is enriched in https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1004405

    We also found that ~40% of the synaptic proteome has a palmitoylated proteo form.

    Best,
    Dale

    3

    2 weeks

    Abagael Lasseigne

    Dale,
    Thank you for this recommendation! I will definitely take a look at this paper!
    Best,
    Abbey

    Have your say

    Your email address will not be published. Required fields are marked *

    This site uses Akismet to reduce spam. Learn how your comment data is processed.

    Sign up to customise the site to your preferences and to receive alerts

    Register here

    Also in the biochemistry category:

    A DNA-based voltmeter for organelles

    Anand Saminathan, John Devany, Kavya S Pillai, et al.



    Selected by Robert Mahen

    Structures of the Otopetrin Proton Channels Otop1 and Otop3

    Kei Saotome, Bochuan Teng, Che Chun (Alex) Tsui, et al.



    Selected by David Wright

    Inactive USP14 and inactive UCHL5 cause accumulation of distinct ubiquitinated proteins in mammalian cells

    Jayashree Chadchankar, Victoria Korboukh, Peter Doig, et al.



    Selected by Mila Basic

    A complex containing lysine-acetylated actin inhibits the formin INF2

    Mu A, Tak Shun Fung, Arminja N. Kettenbach, et al.



    Selected by Laura McCormick

    1

    Super-resolution Molecular Map of Basal Foot Reveals Novel Cilium in Airway Multiciliated Cells

    Quynh Nguyen, Zhen Liu, Rashmi Nanjundappa, et al.



    Selected by Robert Mahen

    Atlas of Subcellular RNA Localization Revealed by APEX-seq

    Furqan M Fazal, Shuo Han, Pornchai Kaewsapsak, et al.

    AND

    Proximity RNA labeling by APEX-Seq Reveals the Organization of Translation Initiation Complexes and Repressive RNA Granules

    Alejandro Padron, Shintaro Iwasaki, Nicholas Ingolia



    Selected by Christian Bates

    Applications, Promises, and Pitfalls of Deep Learning for Fluorescence Image Reconstruction

    Chinmay Belthangady , Loic A. Royer



    Selected by Romain F. Laine

    Activation of intracellular transport by relieving KIF1C autoinhibition

    Nida Siddiqui, Alice Bachmann, Alexander J Zwetsloot, et al.



    Selected by Ben Craske, Thibault Legal and Toni McHugh

    1

    Reduced mitochondrial lipid oxidation leads to fat accumulation in myosteatosis

    Jonathan P Gumucio, Austin H Qasawa, Patrick J Ferrara, et al.



    Selected by Pablo Ranea Robles

    Integrated NMR and cryo-EM atomic-resolution structure determination of a half-megadalton enzyme complex

    Diego Gauto, Leandro Estrozi, Charles Schwieters, et al.



    Selected by Reid Alderson

    1

    Disrupting Transcriptional Feedback Yields an Escape-Resistant Antiviral

    Sonali Chaturvedi, Marie Wolf, Noam Vardi, et al.



    Selected by Pavithran Ravindran

    1

    Structure of a cytochrome-based bacterial nanowire

    David J Filman, Stephen F Marino, Joy E Ward, et al.



    Selected by Amberley Stephens

    Multi-color single molecule imaging uncovers extensive heterogeneity in mRNA decoding

    Sanne Boersma, Deepak Khuperkar, Bram M.P. Verhagen, et al.

    AND

    Live-cell single RNA imaging reveals bursts of translational frameshifting

    Kenneth R Lyon Jr, Luis U Aguilera, Tatsuya Morisaki, et al.



    Selected by Nicola Stevenson

    Retrieving High-Resolution Information from Disordered 2D Crystals by Single Particle Cryo-EM

    Ricardo Righetto, Nikhil Biyani, Julia Kowal, et al.



    Selected by David Wright

    Structural venomics: evolution of a complex chemical arsenal by massive duplication and neofunctionalization of a single ancestral fold

    Sandy Steffany Pineda, Yanni K-Y Chin, Eivind A.B. Undheim, et al.



    Selected by Tessa Sinnige

    Microtubules Gate Tau Condensation to Spatially Regulate Microtubule Functions

    Ruensern Tan, Aileen J. Lam, Tracy Tan, et al.

    AND

    Kinetically distinct phases of tau on microtubules regulate kinesin motors and severing enzymes

    Valerie Siahaan, Jochen Krattenmacher, Amayra Hernandez-Vega, et al.



    Selected by Satish Bodakuntla

    2

    Also in the cell biology category:

    A DNA-based voltmeter for organelles

    Anand Saminathan, John Devany, Kavya S Pillai, et al.



    Selected by Robert Mahen

    Central spindle microtubules are strongly coupled to chromosomes during both anaphase A and anaphase B

    Che-Hang Yu, Stefanie Redemann, Hai-Yin Wu, et al.



    Selected by Federico Pelisch

    1

    Cell growth dilutes the cell cycle inhibitor Rb to trigger cell division

    Evgeny Zatulovskiy, Daniel F. Berenson, Benjamin R. Topacio, et al.



    Selected by Zaki Ahmad

    1

    Minimal membrane interactions conferred by Rheb C-terminal farnesylation are essential for mTORC1 activation

    Shawn M Ferguson, Brittany Angarola



    Selected by Sandra Malmgren Hill

    Mechanical Stretch Kills Transformed Cancer Cells

    Ajay Tijore, Mingxi Yao, Yu-Hsiu Wang, et al.



    Selected by Vibha SINGH

    EHD2-mediated restriction of caveolar dynamics regulates cellular lipid uptake

    Claudia Matthaeus, Ines Lahmann, Severine Kunz, et al.



    Selected by Andreas Müller

    1

    Mechanical Stretch Kills Transformed Cancer Cells

    Ajay Tijore, Mingxi Yao, Yu-Hsiu Wang, et al.



    Selected by Joseph Jose Thottacherry

    Inactive USP14 and inactive UCHL5 cause accumulation of distinct ubiquitinated proteins in mammalian cells

    Jayashree Chadchankar, Victoria Korboukh, Peter Doig, et al.



    Selected by Mila Basic

    A metabolic switch from OXPHOS to glycolysis is essential for cardiomyocyte proliferation in the regenerating heart

    Hessel Honkoop, Dennis de Bakker, Alla Aharonov, et al.



    Selected by Andreas van Impel

    1

    S-acylated Golga7b stabilises DHHC5 at the plasma membrane to regulate desmosome assembly and cell adhesion.

    Keith T Woodley, Mark O Collins



    Selected by Abagael Lasseigne

    3

    A complex containing lysine-acetylated actin inhibits the formin INF2

    Mu A, Tak Shun Fung, Arminja N. Kettenbach, et al.



    Selected by Laura McCormick

    1

    Super-resolution Molecular Map of Basal Foot Reveals Novel Cilium in Airway Multiciliated Cells

    Quynh Nguyen, Zhen Liu, Rashmi Nanjundappa, et al.



    Selected by Robert Mahen

    Single cell RNA-Seq reveals distinct stem cell populations that drive sensory hair cell regeneration in response to loss of Fgf and Notch signaling

    Mark E. Lush, Daniel C. Diaz, Nina Koenecke, et al.

    AND

    Distinct progenitor populations mediate regeneration in the zebrafish lateral line.

    Eric D Thomas, David Raible



    Selected by Rudra Nayan Das

    1

    Actomyosin-II facilitates long-range retrograde transport of large cargoes by controlling axonal radial contractility

    Tong Wang, Wei Li, Sally Martin, et al.



    Selected by Ivana Viktorinová

    Atlas of Subcellular RNA Localization Revealed by APEX-seq

    Furqan M Fazal, Shuo Han, Pornchai Kaewsapsak, et al.

    AND

    Proximity RNA labeling by APEX-Seq Reveals the Organization of Translation Initiation Complexes and Repressive RNA Granules

    Alejandro Padron, Shintaro Iwasaki, Nicholas Ingolia



    Selected by Christian Bates

    Applications, Promises, and Pitfalls of Deep Learning for Fluorescence Image Reconstruction

    Chinmay Belthangady , Loic A. Royer



    Selected by Romain F. Laine
    Close