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C4orf41 and TTC-15 are mammalian TRAPP components with a role at an early stage in ER-to-Golgi trafficking.

Scrivens PJ, Noueihed B, Shahrzad N, Hul S, Brunet S, Sacher M - Mol. Biol. Cell (2011)

Bottom Line: Through a multidisciplinary approach, we demonstrate that the novel proteins are bona fide components of human TRAPP and implicate C4orf41 and TTC-15 (which we call TRAPPC11 and TRAPPC12, respectively) in ER-to-Golgi trafficking at a very early stage.We further present a binary interaction map for all known mammalian TRAPP components and evidence that TRAPP oligomerizes.Our data are consistent with the absence of a TRAPP I-equivalent complex in mammalian cells, suggesting that the fundamental unit of mammalian TRAPP is distinct from that characterized in S. cerevisiae.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Concordia University, Montreal, Quebec, Canada.

ABSTRACT
TRAPP is a multisubunit tethering complex implicated in multiple vesicle trafficking steps in Saccharomyces cerevisiae and conserved throughout eukarya, including humans. Here we confirm the role of TRAPPC2L as a stable component of mammalian TRAPP and report the identification of four novel components of the complex: C4orf41, TTC-15, KIAA1012, and Bet3L. Two of the components, KIAA1012 and Bet3L, are mammalian homologues of Trs85p and Bet3p, respectively. The remaining two novel TRAPP components, C4orf41 and TTC-15, have no homologues in S. cerevisiae. With this work, human homologues of all the S. cerevisiae TRAPP proteins, with the exception of the Saccharomycotina-specific subunit Trs65p, have now been reported. Through a multidisciplinary approach, we demonstrate that the novel proteins are bona fide components of human TRAPP and implicate C4orf41 and TTC-15 (which we call TRAPPC11 and TRAPPC12, respectively) in ER-to-Golgi trafficking at a very early stage. We further present a binary interaction map for all known mammalian TRAPP components and evidence that TRAPP oligomerizes. Our data are consistent with the absence of a TRAPP I-equivalent complex in mammalian cells, suggesting that the fundamental unit of mammalian TRAPP is distinct from that characterized in S. cerevisiae.

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Depletion of TRAPPC8, TRAPPC11, or TRAPPC12 results in Golgi dispersal. HeLa cells were treated with nonspecific siRNA or with siRNA against C8, C11, or C12 as indicated. Cells were stained with antibodies against ERGIC53, GM130, and mannosidase II, as indicated. The bar represents 10 μm. Quantitation of the phenotype using GM130 as a marker showed that 73% (n = 125), 88% (n = 43), and 88% (n = 42) of the cells from the C8, C11, and C12 knockdowns, respectively, displayed fragmented Golgi compared with 6% (n = 97), 2% (n = 52), and 2% (n = 52) from the nonspecific siRNA controls, respectively.
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Figure 3: Depletion of TRAPPC8, TRAPPC11, or TRAPPC12 results in Golgi dispersal. HeLa cells were treated with nonspecific siRNA or with siRNA against C8, C11, or C12 as indicated. Cells were stained with antibodies against ERGIC53, GM130, and mannosidase II, as indicated. The bar represents 10 μm. Quantitation of the phenotype using GM130 as a marker showed that 73% (n = 125), 88% (n = 43), and 88% (n = 42) of the cells from the C8, C11, and C12 knockdowns, respectively, displayed fragmented Golgi compared with 6% (n = 97), 2% (n = 52), and 2% (n = 52) from the nonspecific siRNA controls, respectively.

Mentions: As was the case with C2 or C2L depletion, RNAi against C8, C11, or C12 resulted in Golgi fragmentation in the form of dispersed punctae, as assessed by indirect immunofluorescence of the ER-to-Golgi intermediate compartment (ERGIC), cis- and medial-Golgi markers ERGIC53, GM130, and Golgi α-Mannosidase II (Man II), respectively (Figure 3). The C11 knockdown phenotype is consistent with an earlier study showing a similar Golgi phenotype (Wendler et al., 2010). These results imply that the three novel TRAPP-associated proteins function in the early secretory pathway.


C4orf41 and TTC-15 are mammalian TRAPP components with a role at an early stage in ER-to-Golgi trafficking.

Scrivens PJ, Noueihed B, Shahrzad N, Hul S, Brunet S, Sacher M - Mol. Biol. Cell (2011)

Depletion of TRAPPC8, TRAPPC11, or TRAPPC12 results in Golgi dispersal. HeLa cells were treated with nonspecific siRNA or with siRNA against C8, C11, or C12 as indicated. Cells were stained with antibodies against ERGIC53, GM130, and mannosidase II, as indicated. The bar represents 10 μm. Quantitation of the phenotype using GM130 as a marker showed that 73% (n = 125), 88% (n = 43), and 88% (n = 42) of the cells from the C8, C11, and C12 knockdowns, respectively, displayed fragmented Golgi compared with 6% (n = 97), 2% (n = 52), and 2% (n = 52) from the nonspecific siRNA controls, respectively.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3113772&req=5

Figure 3: Depletion of TRAPPC8, TRAPPC11, or TRAPPC12 results in Golgi dispersal. HeLa cells were treated with nonspecific siRNA or with siRNA against C8, C11, or C12 as indicated. Cells were stained with antibodies against ERGIC53, GM130, and mannosidase II, as indicated. The bar represents 10 μm. Quantitation of the phenotype using GM130 as a marker showed that 73% (n = 125), 88% (n = 43), and 88% (n = 42) of the cells from the C8, C11, and C12 knockdowns, respectively, displayed fragmented Golgi compared with 6% (n = 97), 2% (n = 52), and 2% (n = 52) from the nonspecific siRNA controls, respectively.
Mentions: As was the case with C2 or C2L depletion, RNAi against C8, C11, or C12 resulted in Golgi fragmentation in the form of dispersed punctae, as assessed by indirect immunofluorescence of the ER-to-Golgi intermediate compartment (ERGIC), cis- and medial-Golgi markers ERGIC53, GM130, and Golgi α-Mannosidase II (Man II), respectively (Figure 3). The C11 knockdown phenotype is consistent with an earlier study showing a similar Golgi phenotype (Wendler et al., 2010). These results imply that the three novel TRAPP-associated proteins function in the early secretory pathway.

Bottom Line: Through a multidisciplinary approach, we demonstrate that the novel proteins are bona fide components of human TRAPP and implicate C4orf41 and TTC-15 (which we call TRAPPC11 and TRAPPC12, respectively) in ER-to-Golgi trafficking at a very early stage.We further present a binary interaction map for all known mammalian TRAPP components and evidence that TRAPP oligomerizes.Our data are consistent with the absence of a TRAPP I-equivalent complex in mammalian cells, suggesting that the fundamental unit of mammalian TRAPP is distinct from that characterized in S. cerevisiae.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Concordia University, Montreal, Quebec, Canada.

ABSTRACT
TRAPP is a multisubunit tethering complex implicated in multiple vesicle trafficking steps in Saccharomyces cerevisiae and conserved throughout eukarya, including humans. Here we confirm the role of TRAPPC2L as a stable component of mammalian TRAPP and report the identification of four novel components of the complex: C4orf41, TTC-15, KIAA1012, and Bet3L. Two of the components, KIAA1012 and Bet3L, are mammalian homologues of Trs85p and Bet3p, respectively. The remaining two novel TRAPP components, C4orf41 and TTC-15, have no homologues in S. cerevisiae. With this work, human homologues of all the S. cerevisiae TRAPP proteins, with the exception of the Saccharomycotina-specific subunit Trs65p, have now been reported. Through a multidisciplinary approach, we demonstrate that the novel proteins are bona fide components of human TRAPP and implicate C4orf41 and TTC-15 (which we call TRAPPC11 and TRAPPC12, respectively) in ER-to-Golgi trafficking at a very early stage. We further present a binary interaction map for all known mammalian TRAPP components and evidence that TRAPP oligomerizes. Our data are consistent with the absence of a TRAPP I-equivalent complex in mammalian cells, suggesting that the fundamental unit of mammalian TRAPP is distinct from that characterized in S. cerevisiae.

Show MeSH
Related in: MedlinePlus