细胞功能测定

Protein kinases form one of the largest families of proteins encoded in the human genome, and these enzymes have critical roles in controlling all cellular processes. The abnormal phosphorylation state of proteins is the cause or consequence of many diseases and, for this reason, protein kin ...

A multicellular organism is composed of many types of cells performing specialized functions. Cells have to communicate with each other for the organism to function as a whole. They do so at many levels and by various mechanisms. A cell’s identity is determined by the proteins synthesized within i ...

Mitogen-activated protein (MAP) kinases play an essential role in regulating diverse cellular processes in mammalian cells in response to many extracellular signals (see also Chapter 12, this volume).

The reversible phosphorylation of proteins is a key mechanism whereby signalling cascades involved in the response to extracellular stimuli bring about changes in cellular function. These proteins include the kinases/phosphatases that form such signaling pathways as well as the ...

The AMP-activated protein kinase (AMPK) is the central component of a protein kinase cascade that is activated by cellular stresses causing ATP depletion and has been referred to as a “fuel gauge” or “metabolic sensor” of the eukaryotic cell (1,2). The kinase is activated by phosphorylation by an u ...

Recent studies have determined that a variety of protein tyrosine kinases can be activated by the exposure of cells to oxidative stress (1–3). The stress may arise from chemical agents such as hydrogen peroxide, as well as from irradiation with ultraviolet or ionizing radiation. Oxidative st ...

The DNA-dependent protein kinase, DNA-PK, is required for DNA double-strand break repair and V(D)J recombination (1–3). DNA-PK is composed of a large catalytic subunit of approx 460 kDa (DNA-PKcs) and a heterodimeric DNA targeting subunit, Ku. Ku is composed of 70-kDa and approx 80-kDa subunits (c ...

A variety of genetic disorders involve genome instability and abnormal response to DNA damaging agents. Investigation of these disorders has revealed different metabolic pathways responsible for damage repair on one hand, and for signaling the presence of the damage to cellular regu ...

Nuclear factor-KB (NF-KB) and activator protein 1 (AP-1) are well-characterized ubiquitously expressed transcription factors that play important roles in the response to cellular stress situations. In unstimulated resting cells, NF-KB and AP-1 are inactive. These transcripti ...

Oxidative stress is implicated in a wide range of human diseases as well as0 the ageing process and major efforts have been concentrated on development of markers of this state in cells. The discovery that the expression of the gene which encodes the heme catabolic enzyme, heme-oxygenase-1 (HO-1), ...

Human immunodeficiency virus type-1 (HIV-1) replication and pro viral gene expression are exquisitely responsive to factors that induce cellular stress. Oxidants, ultraviolet (UV) light, osmotic stress, heat shock and pro-inflammatory cytokines all promote proviral gene exp ...

An important component of the stress response, as well as many other biological systems, is the change in relative concentration of specific mRNAs following induction (1). Conventional techniques of differential screening may be sufficient for the detection and identification of so ...

The characteristics of an organism or tissue are determined by the genes expressed within it. The determination of the genomic sequence of higher organisms, including humans, is now a real and attainable goal, as seen by the progress of the Human Genome Mapping Project. This information is needed ...

The heme oxygenase enzymes (HO-1 and HO-2) oxidize heme to biliver-din-IXα (BVIXα), releasing carbon monoxide (CO) and iron (Fig. 1). HO enzymes control the rate of heme degradation and, consequently, also control the redistribution of the heme iron (1). The CO generated from the HO reaction affects ...

Molecular chaperones function in a range of protein homeostatic events, including cotranslational protein folding, assembly and disassembly of protein complexes, and protein transport across membranes. Many molecular chaperones are also known as heat-shock proteins, which ...

Small Hsp’s (sHsp’s) are an ubiquitous but diverse class of proteins that differ from other Hsp families in that only certain short-sequence motifs, the so-called α-crystallin domains and some sequence in the N-terminal parts, are conserved. Characteristic features in common are their low m ...

The p53 protein (reviewed in refs. 1–5) is a latent transcription factor that is activated in response to a variety of cellular stresses, including DNA damage, mitotic spindle damage, heat shock, hypoxia, cytokines, metabolic changes, viral infection, and activated oncogenes, and is consid ...

Small heat-shock proteins (sHsps) are involved in diverse biological phenomena and can act as molecular chaperones in vitro (reviewed in ref. 1, see also Chapter 25). At the posttranslational level, several modifications of sHsp’ have been detected, including phosphorylation, deamid ...

Multicellular animals are exposed routinely to oxidizing chemicals and radiation from the environment, as well as endogenous metabolic by-products that can damage DNA and proteins over the life-span of the cell. Such damage may contribute to tissue injury, promote aging, and is implicat ...

The first preliminary characterization of any newly isolated DNA fragment usually involves restriction site mapping. For this, a family of bacterial enzymes called restriction endonucleases, or restriction enzymes, are utilized. These enzymes recognize specific sequences ...