University of Dundee

About: University of Dundee is a education organization based out in Dundee, United Kingdom. It is known for research contribution in the topics: Population & Protein kinase A. The organization has 19258 authors who have published 39640 publications receiving 1919433 citations. The organization is also known as: Universitas Dundensis & Dundee University.

Phosphorylation of Ser-241 is essential for the activity of 3-phosphoinositide-dependent protein kinase-1: identification of five sites of phosphorylation in vivo

Abstract: 3-phosphoinositide-dependent protein kinase-1 (PDK1) expressed in unstimulated 293 cells was phosphorylated at Ser-25, Ser-241, Ser-393, Ser-396 and Ser-410 and the level of phosphorylation of each site was unaffected by stimulation with insulin-like growth factor-1. Mutation of Ser-241 to Ala abolished PDK1 activity, whereas mutation of the other phosphorylation sites individually to Ala did not affect PDK1 activity. Ser-241, unlike the other phosphorylation sites on PDK1, was resistant to dephosphorylation by protein phosphatase 2A(1). Ser-241 lies in the activation loop of the PDK1 kinase domain between subdomains VII and VIII in the equivalent position to the site that PDK1 phosphorylates on its protein kinase substrates. PDK1 expressed in bacteria was active and phosphorylated at Ser-241, suggesting that PDK1 can phosphorylate itself at this site, leading to its own activation.

The role of cyclic-AMP-dependent protein kinase in the regulation of glycogen metabolism in mammalian skeletal muscle.

Abstract: Publisher Summary This chapter discusses the role of cyclic-AMP-dependent protein kinase in the regulation of glycogen metabolism in mammalian skeletal muscle. When assayed at optimal ATP-Mg-concentrations and in the presence of saturating amounts of Ca2+, purified phosphorylase kinase has a very low activity at physiological pH (6.8) relative to the activity at pH 8.2. Phosphorylation of α subunit of phosphorylase kinase controls the rate of dephosphorylation of the β subunit catalyzed by phosphorylase kinase phosphatase. The conversion of phosphorylase kinase a to phosphorylase b correlates with dephosphorylation of the β subunit, and the rate of dephosphorylation of the enzyme in the absence of divalent cations is determined by the extent of phosphorylation of the α subunit. Phosphorylation of the α subunit alters the conformation of phosphorylase kinase in such a way that it facilitates the action of phosphorylase kinase phosphatase on the β subunit. Cyclic-AMP-dependent protein kinase plays two roles: (1) it activates the enzyme through phosphorylation of the β subunit and (2) it determines the time at which dephosphorylation of the β subunit and inactivation of the enzyme can become rapid through phosphorylation of the α subunit.

Difficulties in Learning and Teaching Programming—Views of Students and Tutors

Abstract: We have conducted a web-based questionnaire on the various concepts and topics of object-oriented programming that students on introductory courses found most difficult to cope with. A statistical analysis of our results shows that those topics that rely on a clear understanding of pointers and memory-related concepts (such as copy constructors and virtual functions) prove to be the most difficult. In other words, we believe these concepts are only hard because of the student's inability to comprehend what is happening to their program in memory, as they are incapable of creating a clear mental model of its execution. These results would suggest that a clearer approach to teaching these topics would be beneficial to students. We are currently working on a visualization-based approach to address these issues.