Growth factors characterization

All of the growth factors characterized so far are proteins (table 24.7). Many of them are cleaved from larger precursors. The 53-amino-acid epidermal growth factor (EGF) is cleaved from a precursor of 1,168 amino acids. This precursor is a membrane-spanning protein, with the EGF moiety and nine related sequences in the extracellular domain. EGF is homologous to several other growth factors,... 

Ikura, T. and Go, N. (1993) Normal Mode Analysis of Mouse Epidermal Growth Factor Characterization of the Harmonic Motion, Proteins Struct. Func. Gen. 16, 423-436. 

These interactions involve adhesion proteins called selectins, which are found both on the rolling leukocytes and on the endothelial cells of the vascular walls. Selectins have a characteristic domain structure, consisting of an N-terminal extracellular lectin domain, a single epidermal growth factor (EGR) domain, a series of two to nine short consensus repeat (SCR) domains, a single transmembrane segment, and a short cytoplasmic domain. Lectin domains, first characterized in plants, bind carbohydrates... 

Extracellular factors that induce mitosis are termed mitogens. Some of these, such as epidermal growth factor (EOF) and fibroblast growth factor (FGF) are now being characterized. 

A factor known as scatter factor has been characterized which causes the break up and stimulates motility of epithelial cell clumps (Stoker et al., 1987). This factor is identical to hepatocyte growth factor and increases the rate of locomotion of several other cell types. Motility factors elaborated from tumor cells are considered to play an important role in metastasis (see later). Guidance of cells by the physical topography of the substratum is another factor that profoundly affects the behavior of cells. 

Basu S., Wickstrom E. Synthesis and characterization of a peptide nucleic acid conjugated to a D-peptide analog of insu-lin-like growth factor 1 for increased cellular uptake. Bioconjug. Chem. 1997 8 481-488. 

Horney, M.J. et al. (2001) Synthesis and characterization of insulin-like growth factor (IGF)-l photoprobes selective for the IgG-binding proteins (IGFBPs) photoaffinity labeling of the IGF-binding domain on IGFBP-2./. Biol. Chem. 276(4), 2880-2889. 

Growth factor administration may also be a useful treatment for neurodegenerative diseases, such as Alzheimer s disease or Parkinson s disease, which are characterized by the degeneration of neuronal cell populations. It was found that the NGF promoted nerve regeneration within conduits at an early stage, but the effect did not last after one month. This was attributed to the rapid decline in NGF concentrations in the conduit due to degradation in aqueous media and leakage from the... 

The differentiation, growth and division of eukaryotic cells is modulated by various influences, of which growth factors are amongst the most important for many cell types. A wide range of polypeptide growth factors have been identified (Table 10.1) and more, undoubtedly, remain to be characterized. Factors that inhibit cell growth also exist. For example, interferons and TNF inhibit proliferation of various cell types. 

TPO is the haemopoietic growth factor now shown to be the primary physiological regulator of platelet production. This molecule may, therefore, represent an important future therapeutic agent in combating thrombocytopenia, a condition characterized by reduced blood platelet levels. The most likely initial TPO therapeutic target is thrombocytopenia induced by cancer chemo- or... 

The best characterized family of MAPKs in the brain are the extracellular signal-regulated protein kinases (ERKs) that are activated by the neurotrophins and related growth factors (Fig. 23-4) [14,15]. The MAPK kinases responsible... 

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