When yeast respond to mating pheromone, they must complete their current round of mitosis and cytokinesis, arrest in G1, and then polarize towards the active pheromone receptor.聽 While the mechanism of G1 arrest is fairly well understood, the mechanisms by which the cell stops the active pheromone receptor from co-opting the polarity machinery before the yeast have finished cytokinesis is not understood.聽 We are interested in desensitization of the pheromone pathway by the Regulator of G-protein Signaling (RGS), Sst2. The RGS serves as a GTPase Activating Protein for the large G-protein, Gpa1, at the top of the pheromone pathway. RGS binding induces the G-protein to turn off, but there are many aspects of RGS signaling to the G-protein that are not understood. It has long been known that the RGS is phosphorylated by MAP Kinase during the pheromone response, but there was no clear physiological outcome from this modification.

We have found that the RGS, Sst2, is phosphorylated during the pheromone response to regulate its interaction with the kelch-repeat protein, Kel1.聽 Kel1 regulates actin polymerization by formins, and also plays a role in the Mitotic Exit Network (MEN).聽 The feedback phosphorylation of the RGS by MAP Kinase during the pheromone response helps the cells prioritize the completion of cytokinesis prior to repurposing the cell polarity machinery for pheromone receptor-mediated polarized growth.聽聽 At later times in the pheromone response, phosphorylation of the RGS alters where MAP Kinase is active relative to the polar cap.

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聽 Bailey EC, Alrowaished SS, Kilroy EA, Crooks ES, Drinkert DM, Karunasiri CM, Belanger JJ, Khalil A, Kelley JB, Henry CA. Skelet Muscle. 2019 Aug 7;9(1):21

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This paper describes the considerations and approaches necessary for quantification of nuclear and cytoplasmic distribution of molecules imaged by fluorescence microscopy. It covers the use of ImageJ for performing the quantitation as well as simple approaches to intensity based segmentation of images for higher throughput measurements.

Kelley JB, Paschal BM. Methods. 2018 Nov 10. pii: S1046-2023(18)30123-3. doi: 10.1016/j.ymeth.2018.11.002.聽 PMID: 30419335

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In collaboration with the Paschal Lab at the University of Virginia, the Kelley Lab has published a new paper in Aging Cell.聽 Kelley Lab members William Simke and Isaac Johnson generated yeast missing a key histone methyltransferase and examined the ability of the cell to properly localize Ran.聽 Ran is the main regulator of nucleocytoplasmic transport, and proper regulation of Ran results in its accumulation in the nucleus.聽 Corroborating the Paschal lab findings using pharmacological inhibitors, we found that proper Ran localization was dependent upon the activity of histone methyl transferase.

Dworak N, Makosa D, Chatterjee M, Jividen K, Yang CS, Snow C, Simke WC, Johnson IG, Kelley JB, Paschal BM. Aging Cell. 2018 Dec 19:e12851. doi: 10.1111/acel.12851.聽 PMID: 30565836

The post Kelley Lab Publishes Paper on Link Between Chromatin Modification State and Nuclear Transport appeared first on Kelley Lab at 91福利.

In Collaboration with the Reines Lab at Emory University, the Kelley Lab has published a new paper in PLoS ONE.

Loya TJ, O’Rourke TW, Simke WC, Kelley JB, Reines D. PLoS One. 2018 Dec 17;13(12):e0209195. doi: 10.1371/journal.pone.0209195. eCollection 2018. PMID: 30557374

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