细胞技术

Although the structures of individual proteins and moderately sized complexes of proteins may be investigated by X-ray crystallography, the interaction between a long polymer, such as a microtubule, and other protein molecules, such as the motor domain of kinesin, need to be studied by elec ...

Stathmin is an important phosphorylation-controlled regulator of microtubule dynamics and plays a crucial role in cell division and cell proliferation. In its non-phosphorylated form, stathmin is the protein that interacts the most tightly with tubulin, in a 2:1 tubulin-stathmin ( ...

Numerous comparisons have shown that confocal imaging of fluorescently labeled samples has superior image clarity compared to traditional epifluorescence microscopy, especially when imaging through thick specimens. Nevertheless, one limitation of confocal microsc ...

In this article, the author describes the needed instrumentation and the methods to be followed for the observation and measurement of the birefringence of single and bundled microtubules and of their ordered arrays using a polarizing microscope. As instruments, the traditional pola ...

Nitric oxide (NO) is a small, labile molecule that plays a key role as an intercellular and intracellular messenger. Interest in the mechanisms by which NO exerts its effects has increased tremendously along with the vast experimental evidence implicating NO in a variety of physiological and ...

There now exists a bewildering array of biological processes in which free radicals have been implicated (1), and we assume that enzymes and structural proteins may be attacked whenever free radicals are generated. As a consequence, oxidative modification of proteins may occur in a variety of ...

Lipid peroxidation has been associated with important pathophysiological events in a variety of diseases, drug toxicities, and traumatic or ischemic injuries. It has been postulated that free radicals and aldehydes generated during this process may be responsible for these effec ...

Normal oxidative metabolism leads to the generation of reactive oxygen species (ROS), in particular, superoxide anion (O2−), and its dismutation product hydrogen peroxide (H2O2), which may escape from the electron-transport chain (1. In addition, oxidative stress may be generated th ...

Molecular oxygen is an excellent acceptor of electrons and is therefore employed by nature for a wide variety of highly important biochemical reactions. The chemical reactivity of oxygen, however, also leads to the formation of oxygen radicals as by-products of metabolism. These radica ...

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 ...