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© The Rockefeller University Press,
0021-9525/1999//1223 $5.00
The Journal of Cell Biology, Volume 147, Number 6,
, 1999 1223-1236
Original Article |
Role for Drs2p, a P-Type Atpase and Potential Aminophospholipid Translocase, in Yeast Late Golgi Function
tr.graham{at}vanderbilt.edu
ADP-ribosylation factor appears to regulate the budding of both COPI and clathrin-coated transport vesicles from Golgi membranes. An arf1
synthetic lethal screen identified SWA3/DRS2, which encodes an integral membrane P-type ATPase and potential aminophospholipid translocase (or flippase). The drs2 null allele is also synthetically lethal with clathrin heavy chain (chc1) temperature-sensitive alleles, but not with mutations in COPI subunits or other SEC genes tested. Consistent with these genetic analyses, we found that the drs2
mutant exhibits late Golgi defects that may result from a loss of clathrin function at this compartment. These include a defect in the Kex2-dependent processing of pro–
-factor and the accumulation of abnormal Golgi cisternae. Moreover, we observed a marked reduction in clathrin-coated vesicles that can be isolated from the drs2
cells. Subcellular fractionation and immunofluorescence analysis indicate that Drs2p localizes to late Golgi membranes containing Kex2p. These observations indicate a novel role for a P-type ATPase in late Golgi function and suggest a possible link between membrane asymmetry and clathrin function at the Golgi complex.
Key Words: adenosine diphosphate–ribosylation factor aminophospholipid translocase clathrin DRS2 trans-Golgi network
© 1999 The Rockefeller University Press
Drs. Chen and Ingram contributed equally to this work and should be considered co–first authors.Abbreviations used in this paper: AP, adaptor protein; ARF, ADP-ribosylation factor; CCV, clathrin-coated vesicle; CPY, carboxypeptidase Y; EM, electron microscopy; HA, hemagglutinin; ORF, open reading frame; PE, phosphatidylethanolamine; PS, phosphatidylserine; ts allele, temperature-sensitive allele.
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