Biology subjects

Koshland, D.

Publications and source records attributed to Koshland, D..

3 recordsLinked to original sources

bioRxiv2017

Synergism between a simple sugar and a small intrinsically disordered protein mitigate the lethal stresses of severe water loss

Anhydrobiotes are rare microbes, plants and animals that tolerate severe water loss. Understanding the molecular basis for their desiccation tolerance may provide novel insights into stress biology and critical tools for engineering drought-tolerant crops. Using the anhydrobiote, budding yeast, we show that trehalose and Hsp12, a small intrinsically disordered protein (sIDP) of the hydrophilin family, synergize to mitigate completely the inviability caused by the lethal stresses of desiccation. We show that these two molecules help to stabilize the activity and prevent aggregation of model proteins both in vivo and in vitro. We also identify a novel role for Hsp12 as a membrane remodeler, a protective feature not shared by another yeast hydrophilin, suggesting that sIDPs have distinct biological functions.

cell biology↗

bioRxiv2017

A role for the Smc3 hinge domain in the maintenance of sister chromatid cohesion

Cohesin is a conserved protein complex required for sister chromatid cohesion, chromosome condensation, DNA damage repair, and regulation of transcription. Although cohesin functions to tether DNA duplexes, the contribution of its individual domains to this activity remains poorly understood. We interrogated the Smc3p subunit of cohesin by random insertion mutagenesis. Analysis of a mutant in the Smc3p hinge revealed an unexpected role for this domain in cohesion maintenance and condensation. Further investigation revealed that the Smc3p hinge functions at a step following cohesins stable binding to chromosomes and independently of Smc3ps regulation by the Eco1p acetyltransferase. Hinge mutant phenotypes resemble loss of Pds5p, which binds opposite the hinge near Smc3ps head domain. We propose that a specific conformation of the Smc3p hinge and Pds5p cooperate to promote cohesion maintenance and condensation.

cell biology↗

bioRxiv2017

Budding yeast Wpl1p regulates cohesin functions in cohesion, condensation and DNA repair by a common mechanism

Cohesin tethers DNA to mediate sister chromatid cohesion, chromosome condensation, and DNA repair. How the cell regulates cohesin to perform these distinct functions remains to be elucidated. One cohesin regulator, Wpl1p, was characterized in the budding yeast, Saccharomyces cerevisiae, as a promoter of cohesion and as an inhibitor of condensation. Here we provide evidence that Wpl1p has an additional function in promoting the timely repair of DNA damage induced during S-phase. In addition to these biological functions, Wpl1p has been implicated as an inhibitor of cohesins ability to stably bind DNA by modulating the interface between two subunits (Mcd1p and Smc3p) of the core cohesin complex. We show that Wpl1p likely modulates this interface to regulate all cohesins biological functions. Furthermore, we show that Wpl1p regulates cohesion and condensation through the formation of a functional complex with another cohesin-associated factor, Pds5p. In contrast, Wpl1p regulates DNA repair independently of its interaction with Pds5p. Together these results suggest that Wpl1p regulates distinct biological functions of cohesin by Pds5p-dependent and - independent modulation of the Smc3p-Mcd1p interface.

genetics↗