Biomedical subjects

Anthony N Anselmo

Publications and source records attributed to Anthony N Anselmo.

4 recordsLinked to original sources

PubMed2006

WNK1 and OSR1 regulate the Na+, K+, 2Cl- cotransporter in HeLa cells.

Oxidative stress-responsive kinase (OSR) 1 and sterile20-related, proline-, alanine-rich kinase (SPAK) are Ste20p-related protein kinases that bind to the sodium, potassium, two chloride cotransporter, NKCC. Here we present evidence that the protein kinase with no lysine [K] (WNK) 1 regulates OSR1, SPAK, and NKCC activities. OSR1 exists in a complex with WNK1 in cells, is activated by recombinant WNK1 in vitro, and is phosphorylated in a WNK1-dependent manner in cells. Depletion of WNK1 from HeLa cells by using small interfering RNA reduces OSR1 kinase activity. In addition, depletion of either WNK1 or OSR1 reduces NKCC activity, indicating that WNK1 and OSR1 are both required for NKCC function. OSR1 and SPAK are likely links between WNK1 and NKCC in a pathway that contributes to volume regulation and blood pressure homeostasis in mammals.

Enzyme Activation↗

PubMed2004

Protein kinase function and glutathionylation.

Intracellular reactive oxygen species are generated as a by-product of normal metabolic processes and can both damage cellular constituents and function as important signalling species. This signalling often involves changes in the thiol redox balance. As an antioxidant, glutathione serves in maintaining the reduced state of cellular protein thiol groups. The paper by Cross and Templeton appearing in this issue of the Biochemical Journal describes a mechanism by which glutathionylation plays a key role in the regulation of the kinase activity of MEKK1 [MAP (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase kinase; MAP3K] in response to oxidative stresses. This type of post-translational-modification glutathionylation may represent a general mechanism by which protein kinase function can be regulated.

Glutathione↗

PubMed2003

Structure of rabbit-muscle glyceraldehyde-3-phosphate dehydrogenase.

The crystal structure of the tetrameric form of D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) isolated from rabbit muscle was solved at 2.4 A resolution after careful dynamic light-scattering experiments to find a suitable buffer for crystallization trials. The refined model has a crystallographic R factor of 20.3%. Here, the first detailed model of a mammalian GAPDH is presented. The cofactor NAD(+) (nicotinamide adenine dinucleotide) is bound to two subunits of the tetrameric enzyme, which is consistent with the negative cooperativity of NAD(+) binding to this enzyme. The structure of rabbit-muscle GAPDH is of interest because it shares 91% sequence identity with the human enzyme; human GAPDH is a potential target for the development of anti-apoptotic drugs. In addition, differences in the cofactor-binding pocket compared with the homology-model structure of GAPDH from the malaria parasite Plasmodium falciparum could be exploited in order to develop novel selective and potential antimalaria drugs.

Amino Acid Sequence↗

PubMed2001

Critical contribution of linker proteins to Raf kinase activation.

Genetic analysis of Ras signaling has unveiled the participation of non-enzymatic accessory proteins in signal transmission. These proteins, KSR, CNK, and Sur-8, can interact with multiple core components of the Ras/MAP kinase cascade and may contribute to the structural organization of this cascade. However, the precise biochemical nature of the contribution of these proteins to Ras signaling is currently unknown. Here we show directly that CNK and KSR are required for stimulus dependent Raf kinase activation. CNK is required for membrane recruitment of Raf, while KSR is likely required to couple Raf to upstream kinases. These results demonstrate that CNK and KSR are integral components of the cellular machinery mediating Raf activation.

Adaptor Proteins, Signal Transducing↗