Protein Networks Supporting AP-3 Function in Targeting Lysosomal Membrane Proteins

Baust, Thorsten; Anitei, Mihaela; Czupalla, Cornelia; Parshyna, Iryna; Bourel-Bonnet, Line; Thiele, Christoph; Krause, Eberhard; Hoflack, Bernard

doi:10.1091/mbc.e08-02-0110

Cited by 58 publications

(50 citation statements)

References 52 publications

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“…It is unlikely that the result of the degranulation assay was severely affected by a general misrouting of LAMP1 in Vit1b-or Vamp8-deficient CTL. Misrouted LAMP1 usually appears at the plasma membrane (35), but cell surface expression of CD107a/ LAMP1 before degranulation as well as the overall expression level was similar in Vti1b-and Vamp8-deficient CTL compared with wildtype and heterozygous CTL. However, we cannot completely exclude that vti1b and VAMP8 might play a role in LAMP1 trafficking.…”

Section: Discussionmentioning

confidence: 89%

The Exocytosis of Lytic Granules Is Impaired in Vti1b- or Vamp8-Deficient CTL Leading to a Reduced Cytotoxic Activity following Antigen-Specific Activation

Dressel

Elsner

Novota

et al. 2010

The Journal of Immunology

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The exocytosis of cytotoxic proteins stored in lytic granules of activated CTL is a key event during killing of target cells. Membrane fusion events that are mediated by soluble N-ethylmaleimide-sensitive-factor attachment protein receptor (SNARE) proteins are crucial, as demonstrated by patients with familial hemophagocytic lymphohistocytosis type 4 who have mutations in the SNARE protein syntaxin-11 that result in an impaired degranulation of cytotoxic cells. We found an increased mRNA expression of the SNARE protein genes Vti1b and Vamp8 during Ag-specific activation of CTL from TCR-transgenic OT-I mice. Therefore, we investigated the cytolytic activity of CTL from TCR-transgenic Vti1b and Vamp8 knockout mice. At 3 d as well as at 4 d of Ag-specific stimulation, the degranulation of CTL was significantly reduced in Vti1b and Vamp8 knockout mice, as determined by cell surface expression of the degranulation marker CD107a. After 3 d of Ag-specific stimulation, the cytolytic activity of Vti1b- and Vamp8-deficient CTL was reduced to ≈50% compared with heterozygous controls. However, 4 d after stimulation, the cytotoxic activity of Vti1b- as well as Vamp8-deficient CTL was not impaired anymore. The capacity of Vti1b- and Vamp8-deficient dendritic cells to process Ags and to stimulate the proliferation of CTL was not reduced, arguing against an indirect effect on the activation of CTL. These findings suggest a role of the SNARE proteins vti1b and vesicle-associated membrane protein 8 in the degranulation of CTL. However, a deficiency can apparently be compensated and affects only transiently the cytotoxic activity of CTL during their development to armed effector cells.

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Section: Discussionmentioning

confidence: 89%

The Exocytosis of Lytic Granules Is Impaired in Vti1b- or Vamp8-Deficient CTL Leading to a Reduced Cytotoxic Activity following Antigen-Specific Activation

Dressel

Elsner

Novota

et al. 2010

The Journal of Immunology

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“…7, F and H). Unlike AP-2, which binds phosphatidylinositol 4,5-bisphosphate, AP-1 and AP-3 preferentially bind to the less negatively charged phosphatidylinositol 4-phosphate and phosphatidylinositol 3-phosphate, respectively (36,37). In particular, phosphatidylinositol 4,5-bisphosphate binding residues Lys-341, Lys-343, Lys-345, and Lys-354 in 2 are replaced by Ser-329, Thr-331, Asp-333, and Asp-342 in 3A (Fig.…”

Section: Resultsmentioning

confidence: 99%

Structural Basis for the Recognition of Tyrosine-based Sorting Signals by the μ3A Subunit of the AP-3 Adaptor Complex

Mardones

Burgos

Lin

et al. 2013

Journal of Biological Chemistry

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Background: Tyrosine-based, YXXØ-type signals mediate protein sorting through binding to adaptor subunits. Results: X-ray crystallography shows how YXXØ signals bind to the immunoglobulin-like fold of 3A. Conclusion: The binding site for YXXØ signals on 3A is similar to that of 2 but distinct from that of 4. Significance: The study explains the basis for the recognition of diverse YXXØ signals by subunits.

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“…The PI3P binding of EPSIN2 seems surprising at first, since PI3P in plants so far has been associated with LE/PVC, and neither EPSIN2 or AP-3 colocalize with commonly used markers for the LE/PVC. However, mammalian AP-3 also preferentially binds PI3P (Baust et al, 2008); therefore, it would be worthwhile to see whether a discrete, AP-3-, EPSIN2-, and clathrin-dependent vacuolar trafficking pathway starts at a PtdIns(3)P-enriched endomembrane compartment or subdomain relatively near the Golgi. EPSIN3 (AT3G59290) is similar to EPSIN2 (>60% sequence identity), but no functional analysis has been performed to date.…”

Section: Epsins and Other Enths: Functionally Diverse In Post-golgi Tmentioning

confidence: 99%

Helping Hands for Budding Prospects: ENTH/ANTH/VHS Accessory Proteins in Endocytosis, Vacuolar Transport, and Secretion

Zouhar

Sauer

2014

The Plant Cell

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Coated vesicles provide a major mechanism for the transport of proteins through the endomembrane system of plants. Transport between the endoplasmic reticulum and the Golgi involves vesicles with COPI and COPII coats, whereas clathrin is the predominant coat in endocytosis and post-Golgi trafficking. Sorting of cargo, coat assembly, budding, and fission are all complex and tightly regulated processes that involve many proteins. The mechanisms and responsible factors are largely conserved in eukaryotes, and increasing organismal complexity tends to be associated with a greater numbers of individual family members. Among the key factors is the class of ENTH/ANTH/VHS domain-containing proteins, which link membrane subdomains, clathrin, and other adapter proteins involved in early steps of clathrin coated vesicle formation. More than 30 Arabidopsis thaliana proteins contain this domain, but their generally low sequence conservation has made functional classification difficult. Reports from the last two years have greatly expanded our knowledge of these proteins and suggest that ENTH/ANTH/VHS domain proteins are involved in various instances of clathrin-related endomembrane trafficking in plants. This review aims to summarize these new findings and discuss the broader context of clathrin-dependent plant vesicular transport.

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Protein Networks Supporting AP-3 Function in Targeting Lysosomal Membrane Proteins

Cited by 58 publications

References 52 publications

The Exocytosis of Lytic Granules Is Impaired in Vti1b- or Vamp8-Deficient CTL Leading to a Reduced Cytotoxic Activity following Antigen-Specific Activation

The Exocytosis of Lytic Granules Is Impaired in Vti1b- or Vamp8-Deficient CTL Leading to a Reduced Cytotoxic Activity following Antigen-Specific Activation

Structural Basis for the Recognition of Tyrosine-based Sorting Signals by the μ3A Subunit of the AP-3 Adaptor Complex

Helping Hands for Budding Prospects: ENTH/ANTH/VHS Accessory Proteins in Endocytosis, Vacuolar Transport, and Secretion

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