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 months

    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

    3 months

    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:

    The autophagic membrane tether ATG2A transfers lipids between membranes

    Shintaro Maeda, Chinatsu Otomo, Takanori Otomo



    Selected by Sandra Malmgren Hill

    LTK is an ER-resident receptor tyrosine kinase that regulates secretion

    Federica G. Centonze, Veronika Reiterer, Karsten Nalbach, et al.



    Selected by Nicola Stevenson

    1

    Plant photoreceptors and their signaling components compete for binding to the ubiquitin ligase COP1 using their VP-peptide motifs

    Kelvin Lau, Roman Podolec, Richard Chappuis, et al.



    Selected by Martin Balcerowicz

    HIV-1 Gag specifically restricts PI(4,5)P2 and cholesterol mobility in living cells creating a nanodomain platform for virus assembly

    C. Favard, J. Chojnacki, P. Merida, et al.



    Selected by Amberley Stephens

    Aqueous synthesis of a small-molecule lanthanide chelator amenable to copper-free click chemistry

    Stephanie Cara Bishop, Robert Winefield, Asokan Anbanandam, et al.



    Selected by Zhang-He Goh

    Hepatocyte-specific deletion of Pparα promotes NASH in the context of obesity

    Marion Regnier, Arnaud Polizzi, Sarra Smati, et al.



    Selected by Pablo Ranea Robles

    Microfluidic protein isolation and sample preparation for high resolution cryo-EM

    Claudio Schmidli, Stefan Albiez, Luca Rima, et al.



    Selected by David Wright

    ENDOSOMAL MEMBRANE TENSION CONTROLS ESCRT-III-DEPENDENT INTRA-LUMENAL VESICLE FORMATION

    Vincent Mercier, Jorge Larios, Guillaume Molinard, et al.



    Selected by Nicola Stevenson

    1

    Dynamic Aha1 Co-Chaperone Binding to Human Hsp90

    Javier Oroz, Laura J Blair, Markus Zweckstetter



    Selected by Reid Alderson

    1

    A DNA-based voltmeter for organelles

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



    Selected by Robert Mahen

    1

    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

    Also in the cell biology category:

    The autophagic membrane tether ATG2A transfers lipids between membranes

    Shintaro Maeda, Chinatsu Otomo, Takanori Otomo



    Selected by Sandra Malmgren Hill

    LTK is an ER-resident receptor tyrosine kinase that regulates secretion

    Federica G. Centonze, Veronika Reiterer, Karsten Nalbach, et al.



    Selected by Nicola Stevenson

    1

    Distinct RhoGEFs activate apical and junctional actomyosin contractility under control of G proteins during epithelial morphogenesis

    Alain Garcia De Las Bayonas, Jean-Marc Philippe, Annemarie C. Lellouch, et al.



    Selected by Ivana Viktorinová

    1

    In vivo glucose imaging in multiple model organisms with an engineered single-wavelength sensor

    Jacob P. Keller, Jonathan S. Marvin, Haluk Lacin, et al.



    Selected by Stephan Daetwyler

    1

    The spindle assembly checkpoint functions during early development in non-chordate embryos

    Janet Chenevert, Marianne Roca, Lydia Besnardeau, et al.



    Selected by Maiko Kitaoka

    Blue light induces neuronal-activity-regulated gene expression in the absence of optogenetic proteins

    Kelsey M. Tyssowski, Jesse M. Gray



    Selected by Zheng-Shan Chong

    Mutations in the Insulator Protein Suppressor of Hairy Wing Induce Genome Instability

    Shih-Jui Hsu, Emily C. Stow, James R. Simmons, et al.



    Selected by Maiko Kitaoka

    1

    Multi-immersion open-top light-sheet microscope for high-throughput imaging of cleared tissues

    Adam K. Glaser, Nicholas P. Reder, Ye Chen, et al.



    Selected by Tim Fessenden

    1

    ATAT1-enriched vesicles promote microtubule acetylation via axonal transport

    Aviel Even, Giovanni Morelli, Chiara Scaramuzzino, et al.



    Selected by Stephen Royle

    1

    HIV-1 Gag specifically restricts PI(4,5)P2 and cholesterol mobility in living cells creating a nanodomain platform for virus assembly

    C. Favard, J. Chojnacki, P. Merida, et al.



    Selected by Amberley Stephens

    Hepatocyte-specific deletion of Pparα promotes NASH in the context of obesity

    Marion Regnier, Arnaud Polizzi, Sarra Smati, et al.



    Selected by Pablo Ranea Robles

    Mitochondrial biogenesis is transcriptionally repressed in lysosomal lipid storage diseases

    King Faisal Yambire, Lorena Fernandez-Mosquera, Robert Steinfeld, et al.



    Selected by Sandra Franco Iborra

    1

    Thyroid hormone regulates distinct paths to maturation in pigment cell lineages

    Lauren Saunders, Abhishek Mishra, Andrew J Aman, et al.



    Selected by Hannah Brunsdon

    1

    Kinesin-6 Klp9 plays motor-dependent and -independent roles in collaboration with Kinesin-5 Cut7 and the microtubule crosslinker Ase1 in fission yeast

    Masashi Yukawa, Masaki Okazaki, Yasuhiro Teratani, et al.



    Selected by I. Bouhlel

    A pair of E3 ubiquitin ligases compete to regulate filopodial dynamics and axon guidance

    Nicholas P Boyer, Laura E McCormick, Fabio L Urbina, et al.



    Selected by Angika Basant

    1

    SorCS1-mediated Sorting of Neurexin in Dendrites Maintains Presynaptic Function

    Luis Filipe Ribeiro, Ben Verpoort, Julie Nys, et al.



    Selected by Carmen Adriaens

    1

    Close