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Medical Biochemistry Commons

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Full-Text Articles in Medical Biochemistry

A Ypt/Rab Effector Complex Containing The Sec1 Homolog Vps33p Is Required For Homotypic Vacuole Fusion, Darren F. Seals, Gary Eitzen, Nathan Margolis, William T. Wickner, Albert Price Aug 2000

A Ypt/Rab Effector Complex Containing The Sec1 Homolog Vps33p Is Required For Homotypic Vacuole Fusion, Darren F. Seals, Gary Eitzen, Nathan Margolis, William T. Wickner, Albert Price

Dartmouth Scholarship

Yeast vacuoles undergo priming, docking, and homotypic fusion, although little has been known of the connections between these reactions. Vacuole-associated Vam2p and Vam6p (Vam2/6p) are components of a 65S complex containing SNARE proteins. Upon priming by Sec18p/NSF and ATP, Vam2/6p is released as a 38S subcomplex that binds Ypt7p to initiate docking. We now report that the 38S complex consists of both Vam2/6p and the class C Vps proteins [Reider, S. E. and Emr, S. D. (1997) Mol. Biol. Cell 8, 2307-2327]. This complex includes Vps33p, a member of the Sec1 family of proteins that bind t-SNAREs. We term this …


A New Role For A Snare Protein As A Regulator Of The Ypt7/Rab-Dependent Stage Of Docking, Christian Ungermann, Albert Price, William Wickner Aug 2000

A New Role For A Snare Protein As A Regulator Of The Ypt7/Rab-Dependent Stage Of Docking, Christian Ungermann, Albert Price, William Wickner

Dartmouth Scholarship

The homotypic fusion of yeast vacuoles occurs in an ordered cascade of priming, docking, and fusion. The linkage between these steps has so far remained unclear. We now report that Vam7p (the vacuolar SNAP-23/25 homolog) signals from the cis-SNARE complex to Ypt7p (the vacuolar Rab/Ypt) to initiate the docking process. After Vam7p has been released from the cis-SNARE complex by Sec18p-mediated priming, it is still required for Ypt7p-dependent docking and it needs Ypt7p to remain on the vacuole.


Asymmetric Requirements For A Rab Gtpase And Snare Proteins In Fusion Of Copii Vesicles With Acceptor Membranes, Xiaochun Cao, Charles Barlowe Apr 2000

Asymmetric Requirements For A Rab Gtpase And Snare Proteins In Fusion Of Copii Vesicles With Acceptor Membranes, Xiaochun Cao, Charles Barlowe

Dartmouth Scholarship

Soluble NSF attachment protein receptor (SNARE) proteins are essential for membrane fusion in transport between the yeast ER and Golgi compartments. Subcellular fractionation experiments demonstrate that the ER/Golgi SNAREs Bos1p, Sec22p, Bet1p, Sed5p, and the Rab protein, Ypt1p, are distributed similarly but localize primarily with Golgi membranes. All of these SNARE proteins are efficiently packaged into COPII vesicles and suggest a dynamic cycling of SNARE machinery between ER and Golgi compartments. Ypt1p is not efficiently packaged into vesicles under these conditions. To determine in which membranes protein function is required, temperature-sensitive alleles of BOS1, BET1, SED5, SLY1, and YPT1 that …


Auto-Inhibition Of Ets-1 Is Counteracted By Dna Binding Cooperativity With Core-Binding Factor Α2, Tamara L. Goetz, Ting-Lei Gu, Nancy A. Speck, Barbara J. Graves Jan 2000

Auto-Inhibition Of Ets-1 Is Counteracted By Dna Binding Cooperativity With Core-Binding Factor Α2, Tamara L. Goetz, Ting-Lei Gu, Nancy A. Speck, Barbara J. Graves

Dartmouth Scholarship

Auto-inhibition is a common transcriptional control mechanism that is well characterized in the regulatory transcription factor Ets-1. Autoinhibition of Ets-1 DNA binding works through an inhibitory module that exists in two conformations. DNA binding requires a change in the inhibitory module from the packed to disrupted conformation. This structural switch provides a mechanism to tightly regulate Ets-1 DNA binding. We report that the Ets-1 partner protein core-binding factor α2 (CBFα2; also known as AML1 or PEBP2) stimulates Ets-1 DNA binding and counteracts auto-inhibition. Support for this conclusion came from three observations. First, the level of cooperative DNA binding (10-fold) was …