TANGO1 builds a machine for collagen export by recruiting and spatially organizing COPII, tethers and membranes
ELIFE
Authors: Raote, Ishier; Ortega-Bellido, Maria; Santos, Antonio J. M.; Foresti, Ombretta; Zhang, Chong; Garcia-Parajo, Maria F.; Campelo, Felix; Malhotra, Vivek
Abstract
Collagen export from the endoplasmic reticulum (ER) requires TANGO1, COPII coats, and retrograde fusion of ERGIC membranes. How do these components come together to produce a transport carrier commensurate with the bulky cargo collagen? TANGO1 is known to form a ring that corrals COPII coats, and we show here how this ring or fence is assembled. Our data reveal that a TANGO1 ring is organized by its radial interaction with COPII, and lateral interactions with cTAGE5, TANGO1-short or itself. Of particular interest is the finding that TANGO1 recruits ERGIC membranes for collagen export via the NRZ (NBAS/RINT1/ZW10) tether complex. Therefore, TANGO1 couples retrograde membrane flow to anterograde cargo transport. Without the NRZ complex, the TANGO1 ring does not assemble, suggesting its role in nucleating or stabilising this process. Thus, coordinated capture of COPII coats, cTAGE5, TANGO1-short, and tethers by TANGO1 assembles a collagen export machine at the ER.
The rough deal protein is a new kinetochore component required for accurate chromosome segregation in Drosophila
JOURNAL OF CELL SCIENCE
Authors: Scaerou, F; Aguilera, I; Saunders, R; Kane, N; Blottiere, L; Karess, R
Abstract
Mutations in the rough deal (rod) gene of Drosophila greatly increase the missegregation of sister chromatids during mitosis, suggesting a role for this gene product in spindle or kinetochore function. The activity provided by rod also appears to be necessary for the recruitment of two known kinetochore components, Zw10 and cytoplasmic dynein, In this paper we describe the cloning of rough deal and an initial cytological characterization of its product. The Rod protein shares no identifiable structural motif with other known proteins, although apparent homologs exist in the genomes of nematode and man. By immunocytochemistry we show that Rod displays a dynamic intracellular staining pattern, localizing first to kinetochores in prometaphase, but moving to kinetochore microtubules at metaphase, Early in anaphase the protein is once again restricted to the kinetochores, where it persists until the end of telophase, This behavior is in all respects similar to that described for Zw10, and suggests that the proteins function together.
COA
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