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Syntaxin 16 is a master recruitment factor for cytokinesis.

Neto H, Kaupisch A, Collins LL, Gould GW - Mol. Biol. Cell (2013)

Bottom Line: However, it is not clear how either of these complexes is targeted to the midbody and whether their delivery is coordinated.Although membrane traffic is known to play an important role in cytokinesis, the contribution and identity of intracellular SNAREs to cytokinesis remain unclear.Here we demonstrate that syntaxin 16 is a key regulator of cytokinesis, as it is required for recruitment of both recycling endosome-associated Exocyst and ESCRT machinery during late telophase, and therefore that these two distinct facets of cytokinesis are inextricably linked.

View Article: PubMed Central - PubMed

Affiliation: Henry Wellcome Laboratory of Cell Biology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom.

ABSTRACT
Recently it was shown that both recycling endosome and endosomal sorting complex required for transport (ESCRT) components are required for cytokinesis, in which they are believed to act in a sequential manner to bring about secondary ingression and abscission, respectively. However, it is not clear how either of these complexes is targeted to the midbody and whether their delivery is coordinated. The trafficking of membrane vesicles between different intracellular organelles involves the formation of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes. Although membrane traffic is known to play an important role in cytokinesis, the contribution and identity of intracellular SNAREs to cytokinesis remain unclear. Here we demonstrate that syntaxin 16 is a key regulator of cytokinesis, as it is required for recruitment of both recycling endosome-associated Exocyst and ESCRT machinery during late telophase, and therefore that these two distinct facets of cytokinesis are inextricably linked.

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Sx16-ΔTM does not prevent the midbody accumulation of centriolin. HeLa cells were infected with Sx16-ΔTM or Sx12-ΔTM virus as described and immunostained for centriolin (green) or tubulin (red). Representative images from five independent experiments of this type. Asterisk indicates the midbody ring-like structure. Bottom, typical higher-magnification images of the midbody areas.
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Figure 6: Sx16-ΔTM does not prevent the midbody accumulation of centriolin. HeLa cells were infected with Sx16-ΔTM or Sx12-ΔTM virus as described and immunostained for centriolin (green) or tubulin (red). Representative images from five independent experiments of this type. Asterisk indicates the midbody ring-like structure. Bottom, typical higher-magnification images of the midbody areas.

Mentions: Rab11 interacts with the Exocyst complex, and depletion of the Exocyst both inhibits cytokinesis and prevents accumulation of vesicles in the midbody (Zhang et al., 2004; Fielding et al., 2005). Given the lack of localization of Rab11 to the midbody, we tested the hypothesis that Sx16-ΔTM may impede the delivery of Exocyst components to the midbody. We observed profound alterations in Exocyst distribution in cells expressing Sx16-ΔTM compared with controls. As previously reported (Fielding et al., 2005; Gromley et al., 2005; Martin-Cuadrado et al., 2005), we also observed that Sec3, Sec6, Sec8, Sec15, and Exo70 localize to a ring-like structure in the midbody in late telophase in control cells (unpublished data) and cells infected with Sx12-ΔTM (Figure 5). However, in cells expressing Sx16-ΔTM this characteristic ring structure was consistently absent. Instead these proteins appeared to populate multiple diffuse punctae throughout the intercellular bridge (Figure 5). Similar results were obtained upon Sx16-knockdown using siRNA (unpublished data). Arf6 accumulation in the intercellular bridge may also be involved in the delivery of recycling endosomes and interaction with the Exocyst (Fielding et al., 2005). We therefore examined the distribution of Arf6 in telophase in cells depleted of Sx16 or cells expressing Sx16-ΔTM (Supplemental Figure S2). Arf6 localization to the midbody was not affected by either manipulation. These data suggest that Sx16 is required for both the trafficking of Rab11 into the furrow and the delivery of Exocyst components into the midbody of dividing cells. Previous studies established that centriolin is essential for the anchoring of Exocyst components in the midbody of dividing cells (Gromley et al., 2005). Centriolin appears as a ring-like structure at the midbody in late telophase, and this structure was observed in cells overexpressing either Sx12-ΔTM or Sx16-ΔTM, suggesting that the mechanism by which centriolin accumulates at the midzone is not impaired by Sx16-ΔTM expression (Figure 6).


Syntaxin 16 is a master recruitment factor for cytokinesis.

Neto H, Kaupisch A, Collins LL, Gould GW - Mol. Biol. Cell (2013)

Sx16-ΔTM does not prevent the midbody accumulation of centriolin. HeLa cells were infected with Sx16-ΔTM or Sx12-ΔTM virus as described and immunostained for centriolin (green) or tubulin (red). Representative images from five independent experiments of this type. Asterisk indicates the midbody ring-like structure. Bottom, typical higher-magnification images of the midbody areas.
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Related In: Results  -  Collection

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Figure 6: Sx16-ΔTM does not prevent the midbody accumulation of centriolin. HeLa cells were infected with Sx16-ΔTM or Sx12-ΔTM virus as described and immunostained for centriolin (green) or tubulin (red). Representative images from five independent experiments of this type. Asterisk indicates the midbody ring-like structure. Bottom, typical higher-magnification images of the midbody areas.
Mentions: Rab11 interacts with the Exocyst complex, and depletion of the Exocyst both inhibits cytokinesis and prevents accumulation of vesicles in the midbody (Zhang et al., 2004; Fielding et al., 2005). Given the lack of localization of Rab11 to the midbody, we tested the hypothesis that Sx16-ΔTM may impede the delivery of Exocyst components to the midbody. We observed profound alterations in Exocyst distribution in cells expressing Sx16-ΔTM compared with controls. As previously reported (Fielding et al., 2005; Gromley et al., 2005; Martin-Cuadrado et al., 2005), we also observed that Sec3, Sec6, Sec8, Sec15, and Exo70 localize to a ring-like structure in the midbody in late telophase in control cells (unpublished data) and cells infected with Sx12-ΔTM (Figure 5). However, in cells expressing Sx16-ΔTM this characteristic ring structure was consistently absent. Instead these proteins appeared to populate multiple diffuse punctae throughout the intercellular bridge (Figure 5). Similar results were obtained upon Sx16-knockdown using siRNA (unpublished data). Arf6 accumulation in the intercellular bridge may also be involved in the delivery of recycling endosomes and interaction with the Exocyst (Fielding et al., 2005). We therefore examined the distribution of Arf6 in telophase in cells depleted of Sx16 or cells expressing Sx16-ΔTM (Supplemental Figure S2). Arf6 localization to the midbody was not affected by either manipulation. These data suggest that Sx16 is required for both the trafficking of Rab11 into the furrow and the delivery of Exocyst components into the midbody of dividing cells. Previous studies established that centriolin is essential for the anchoring of Exocyst components in the midbody of dividing cells (Gromley et al., 2005). Centriolin appears as a ring-like structure at the midbody in late telophase, and this structure was observed in cells overexpressing either Sx12-ΔTM or Sx16-ΔTM, suggesting that the mechanism by which centriolin accumulates at the midzone is not impaired by Sx16-ΔTM expression (Figure 6).

Bottom Line: However, it is not clear how either of these complexes is targeted to the midbody and whether their delivery is coordinated.Although membrane traffic is known to play an important role in cytokinesis, the contribution and identity of intracellular SNAREs to cytokinesis remain unclear.Here we demonstrate that syntaxin 16 is a key regulator of cytokinesis, as it is required for recruitment of both recycling endosome-associated Exocyst and ESCRT machinery during late telophase, and therefore that these two distinct facets of cytokinesis are inextricably linked.

View Article: PubMed Central - PubMed

Affiliation: Henry Wellcome Laboratory of Cell Biology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom.

ABSTRACT
Recently it was shown that both recycling endosome and endosomal sorting complex required for transport (ESCRT) components are required for cytokinesis, in which they are believed to act in a sequential manner to bring about secondary ingression and abscission, respectively. However, it is not clear how either of these complexes is targeted to the midbody and whether their delivery is coordinated. The trafficking of membrane vesicles between different intracellular organelles involves the formation of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes. Although membrane traffic is known to play an important role in cytokinesis, the contribution and identity of intracellular SNAREs to cytokinesis remain unclear. Here we demonstrate that syntaxin 16 is a key regulator of cytokinesis, as it is required for recruitment of both recycling endosome-associated Exocyst and ESCRT machinery during late telophase, and therefore that these two distinct facets of cytokinesis are inextricably linked.

Show MeSH
Related in: MedlinePlus