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Actin polymerization driven by WASH causes V-ATPase retrieval and vesicle neutralization before exocytosis.

Carnell M, Zech T, Calaminus SD, Ura S, Hagedorn M, Johnston SA, May RC, Soldati T, Machesky LM, Insall RH - J. Cell Biol. (2011)

Bottom Line: Similar results occur when actin polymerization is blocked with latrunculin.V-ATPases are known to bind avidly to F-actin.Our data imply a new mechanism, actin-mediated sorting, in which WASH and the Arp2/3 complex polymerize actin on vesicles to drive the separation and recycling of proteins such as the V-ATPase.

View Article: PubMed Central - HTML - PubMed

Affiliation: Cancer Research UK Beatson Institute for Cancer Research, Bearsden, Glasgow G61 1BD, Scotland, UK.

ABSTRACT
WASP and SCAR homologue (WASH) is a recently identified and evolutionarily conserved regulator of actin polymerization. In this paper, we show that WASH coats mature Dictyostelium discoideum lysosomes and is essential for exocytosis of indigestible material. A related process, the expulsion of the lethal endosomal pathogen Cryptococcus neoformans from mammalian macrophages, also uses WASH-coated vesicles, and cells expressing dominant negative WASH mutants inefficiently expel C. neoformans. D. discoideum WASH causes filamentous actin (F-actin) patches to form on lysosomes, leading to the removal of vacuolar adenosine triphosphatase (V-ATPase) and the neutralization of lysosomes to form postlysosomes. Without WASH, no patches or coats are formed, neutral postlysosomes are not seen, and indigestible material such as dextran is not exocytosed. Similar results occur when actin polymerization is blocked with latrunculin. V-ATPases are known to bind avidly to F-actin. Our data imply a new mechanism, actin-mediated sorting, in which WASH and the Arp2/3 complex polymerize actin on vesicles to drive the separation and recycling of proteins such as the V-ATPase.

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The role of WASH and actin in lysosome neutralization. A schematic diagram of the model proposed in this paper: (a) WASH recruited to acidic lysosomes; (b) WASH puncta cause local actin polymerization, and F-actin binds to V-ATPase; (c) small recycling vesicles bud off, and V-ATPase is recruited by WASH/F-actin; (d) loss of V-ATPase causes the vesicle to neutralize and mature to postlysosome; (e) WASH is removed some time after neutralization.
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fig5: The role of WASH and actin in lysosome neutralization. A schematic diagram of the model proposed in this paper: (a) WASH recruited to acidic lysosomes; (b) WASH puncta cause local actin polymerization, and F-actin binds to V-ATPase; (c) small recycling vesicles bud off, and V-ATPase is recruited by WASH/F-actin; (d) loss of V-ATPase causes the vesicle to neutralize and mature to postlysosome; (e) WASH is removed some time after neutralization.

Mentions: Altogether, our data show that the role of WASH in D. discoideum is to cause new actin polymerization on mature lysosomes, and the role of this F-actin is to bind to the V-ATPase and sort it to recycling vesicles (Fig. 5). This allows the lysosome to neutralize before being exocytosed. In the absence of WASH, the V-ATPase remains on the lysosome, which therefore remains acidic, immature, and unable to exocytose.


Actin polymerization driven by WASH causes V-ATPase retrieval and vesicle neutralization before exocytosis.

Carnell M, Zech T, Calaminus SD, Ura S, Hagedorn M, Johnston SA, May RC, Soldati T, Machesky LM, Insall RH - J. Cell Biol. (2011)

The role of WASH and actin in lysosome neutralization. A schematic diagram of the model proposed in this paper: (a) WASH recruited to acidic lysosomes; (b) WASH puncta cause local actin polymerization, and F-actin binds to V-ATPase; (c) small recycling vesicles bud off, and V-ATPase is recruited by WASH/F-actin; (d) loss of V-ATPase causes the vesicle to neutralize and mature to postlysosome; (e) WASH is removed some time after neutralization.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3105540&req=5

fig5: The role of WASH and actin in lysosome neutralization. A schematic diagram of the model proposed in this paper: (a) WASH recruited to acidic lysosomes; (b) WASH puncta cause local actin polymerization, and F-actin binds to V-ATPase; (c) small recycling vesicles bud off, and V-ATPase is recruited by WASH/F-actin; (d) loss of V-ATPase causes the vesicle to neutralize and mature to postlysosome; (e) WASH is removed some time after neutralization.
Mentions: Altogether, our data show that the role of WASH in D. discoideum is to cause new actin polymerization on mature lysosomes, and the role of this F-actin is to bind to the V-ATPase and sort it to recycling vesicles (Fig. 5). This allows the lysosome to neutralize before being exocytosed. In the absence of WASH, the V-ATPase remains on the lysosome, which therefore remains acidic, immature, and unable to exocytose.

Bottom Line: Similar results occur when actin polymerization is blocked with latrunculin.V-ATPases are known to bind avidly to F-actin.Our data imply a new mechanism, actin-mediated sorting, in which WASH and the Arp2/3 complex polymerize actin on vesicles to drive the separation and recycling of proteins such as the V-ATPase.

View Article: PubMed Central - HTML - PubMed

Affiliation: Cancer Research UK Beatson Institute for Cancer Research, Bearsden, Glasgow G61 1BD, Scotland, UK.

ABSTRACT
WASP and SCAR homologue (WASH) is a recently identified and evolutionarily conserved regulator of actin polymerization. In this paper, we show that WASH coats mature Dictyostelium discoideum lysosomes and is essential for exocytosis of indigestible material. A related process, the expulsion of the lethal endosomal pathogen Cryptococcus neoformans from mammalian macrophages, also uses WASH-coated vesicles, and cells expressing dominant negative WASH mutants inefficiently expel C. neoformans. D. discoideum WASH causes filamentous actin (F-actin) patches to form on lysosomes, leading to the removal of vacuolar adenosine triphosphatase (V-ATPase) and the neutralization of lysosomes to form postlysosomes. Without WASH, no patches or coats are formed, neutral postlysosomes are not seen, and indigestible material such as dextran is not exocytosed. Similar results occur when actin polymerization is blocked with latrunculin. V-ATPases are known to bind avidly to F-actin. Our data imply a new mechanism, actin-mediated sorting, in which WASH and the Arp2/3 complex polymerize actin on vesicles to drive the separation and recycling of proteins such as the V-ATPase.

Show MeSH
Related in: MedlinePlus