A genome-wide screen revealed previously unidentified components required for transport and Golgi organization (TANGO). We now provide evidence that one of these proteins, TANGO1, is an integral membrane protein localized to endoplasmic reticulum (ER) exit sites, with a luminal SH3 domain and a cytoplasmic proline-rich domain (PRD). Knockdown of TANGO1 inhibits export of bulky collagen VII from the ER. The SH3 domain of TANGO1 binds to collagen VII; the PRD binds to the COPII coat subunits, Sec23/24. In this scenario, PRD binding to Sec23/24 subunits could stall COPII carrier biogenesis to permit the luminal domain of TANGO1 to guide SH3-bound cargo into a growing carrier. All cells except those of hematopoietic origin express TANGO1. We propose that TANGO1 exports other cargoes in cells that do not secrete collagen VII. However, TANGO1 does not enter the budding carrier, which represents a unique mechanism to load cargo into COPII carriers.

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A Visit to the Wildlife Refuges on the Gulf of Mexico by Fred G. Bard, Saskatchewan Museum of Natural History Photo by F. W. Lahrman Whooping Cranes at the Aransas Refuge In the latter part of February and early part of March, Fred Lahrman and I visited several of the wildlife refuges on the Gulf of Mexico. The principal reason for our trip was to see the Whooping Cranes at home: the captive birds at the Audubon Photo by F. W. Lahrman Captive Whooping Crane Audubon Park Zoo