No description available.

No description available.

No description available.

Dictyostelium myosin heavy chain kinase A (MHCK A) and mammalian transient receptor potential melastatin-related 7 (TRPM7) are two divergent members of a family of atypical protein kinases called the alpha kinases. The crystal structures of the alpha-kinase domains of MHCK A (A-CAT, residues 552-841) and mouse TRPM7 (TRPM7-CAT, residues 1548-1862) are very similar. In both cases a C-terminal tail (C-tail) sequence (A-CAT, residues 806-841 and TRPM7-CAT, residues 1819-1862) is missing from the crystal structure. Here I show that the unstructured C-tail is required for the catalytic activity of A-CAT and TRPM7-CAT. Truncation of the C-tail of A-CAT to residue 823 decreased kinase activity by ~98% and ATPase activity by ~97%. Truncation of the C-tail of TRPM7-CAT to residue 1827 decreased kinase activity by ~97% and ATPase activity by ~58%. Ligation of the C-tail sequence of MHCK B (residues 326-354) to A-CAT-802 (residues 552-802), fully rescued kinase activity. Alignment of the C-tail sequences of MHCK A-D revealed a conserved Gly-Thr-hydrophobic motif. Previous work has shown that in A-CAT, the conserved threonine (T825) is a site of autophosphorylation. Mutation of the T825 to alanine reduced A-CAT kinase and ATPase activities by 97%, whereas mutation to serine decreased kinase and ATPase rates by 85% and 60%, respectively. This result is consistent with the finding that A-CAT strongly prefers to phosphorylate threonine residues. Surprisingly, mutation of T825 to glutamic acid reduced kinase activity by ~93% and ATPase activity by ~96%. This result suggests that glutamic acid does not properly mimic phosphothreonine in this situation, or that the free hydroxyl group of T825 is required for the catalytic activity of A-CAT. Mutation of T825 to alanine or glutamic acid in full-length MHCK A reduced kinase activity by ~90% and ATPase activity by ~40%. Further studies are required to determine if the C-tail of TRPM7-CAT also contains an essential threonine residue. / Thesis (Master, Biochemistry) -- Queen's University, 2010-02-11 11:23:04.195

The activation of the protein tyrosine kinase (PTK) ZAP-70 is fundamental to T cell receptor (TCR) signal transduction. TCR engagement induces raft-association of ZAP-70 and juxtaposes the cytoplasmic ZAP-70 with the raft-enriched Lck, which phosphorylates and activates ZAP-70. The active ZAP-70, cooperatively with Lck, initiates multiple intracellular pathways eventually leading to T cell activation and IL-2 production. Here, we describe the serine phosphorylation on ZAP-70 on the highly conserved S520DVWS524 motif, and investigate its role in coupling ZAP-70 with TCR signal transduction.

No description available.

Akt activation mediates increases in glycogen synthesis in response to insulin in humans, while extracellular signal-regulated kinase (ERK) activation increases gene transcription and protein translation in response to endurance and resistance exercise. Akt activation increases only in response to intense muscle contractions and during hypertrophy in rats. No study has examined Akt and ERK activation with increasing numbers of intense muscle contractions in humans. Therefore, the primary objectives of this investigation were to determine if Akt activation increases in response to resistance exercise in humans, and to compare the changes in Akt and ERK activation in response to increasing numbers of muscle contractions.Akt and ERK activation were compared in muscle biopsy samples from 7 men before (Pre) and after (Post) knee extension and control protocols using enzyme linkedimmunosorbent assays. Baseline information was obtained including body composition and maximal strength (1-RM). Subjects were familiarized with knee extensions performed at 70% of 1-RM and a specified repetition cadence (2sec up, 2sec down). Once/wk, subjects performed one protocol in random order: 1 repetition (rep), 10reps, 3 sets of l0reps (3x10), or 6min of sitting. Akt activation decreased 42%, while ERK activation increased 108% in response to 3x10 (p<0.05). Akt and ERK activation did not change with 1 and 10reps, and thus their responses were not dose-dependent with resistance exercise in humans. The findings from this study represent the first indication that Akt activation is reduced in response to resistance exercise in human skeletal muscle, possibly to help mediate reductions in glycogen synthesis. / Human Performance Laboratory

Thesis (Ph. D.)--School of Biological Sciences. University of Missouri--Kansas City, 2006. / "A dissertation in molecular biology and biochemistry and cell biology and biophysics." Advisor: Gerald M. Carlson. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed Nov. 9, 2007. Includes bibliographical references (leaves 103-113). Online version of the print edition.

Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 1999. / Bibliography: p. 143-160.

Thesis (Ph.D.)--University of Adelaide, Dept. of Molecular Biosciences, 2002. / "August 2002." Bibliography: p. 157-169.