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Intercellular Signaling Peptides and Proteins

Definition: Regulatory proteins and peptides that are signaling molecules involved in the process of PARACRINE COMMUNICATION. They are generally considered factors that are expressed by one cell and are responded to by receptors on another nearby cell. They are distinguished from HORMONES in that their actions are local rather than distal.
Notes: coordinate with PARACRINE COMMUNICATION (NIM) if hormone action is localized
Also Called: Paracrine Peptide Factors,Paracrine Protein Factors

Intercellular Signaling Peptides and Proteins Categories.
Angiogenic Proteins - Intercellular signaling peptides and proteins that regulate the proliferation of new blood vessels under normal physiological conditions (ANGIOGENESIS, PHYSIOLOGICAL). Aberrant expression of angiogenic proteins during disease states such as tumorigenesis can also result in PATHOLOGICAL ANGIOGENESIS.
Endothelial Growth Factors - These growth factors are soluble mitogens secreted by a variety of organs. The factors are a mixture of two single chain polypeptides which have affinity to heparin. Their molecular weight are organ and species dependent. They have mitogenic and chemotactic effects and can stimulate endothelial cells to grow and synthesize DNA. The factors are related to both the basic and acidic FIBROBLAST GROWTH FACTORS but have different amino acid sequences.
Ephrins - Signalling proteins that are ligands for the EPH FAMILY RECEPTORS. They are membrane-bound proteins that are attached to the CELL MEMBRANE either through a GLYCOINOSITOL PHOSPHOLIPID MEMBRANE ANCHOR or through a transmembrane domain. Many of the ephrins are considered important intercellular signalling molecules that control morphogenic changes during embryogenesis.
Fibroblast Growth Factors - A family of small polypeptide growth factors that share several common features including a strong affinity for HEPARIN, and a central barrel-shaped core region of 140 amino acids that is highly homologous between family members. Although originally studied as proteins that stimulate the growth of fibroblasts this distinction is no longer a requirement for membership in the fibroblast growth factor family.
Nerve Growth Factors - Factors which enhance the growth potentialities of sensory and sympathetic nerve cells.
Neuroleukin - Neuronal growth factor and lymphokine product of lectin-stimulated T-cells which induces immunoglobulin secretion. Its amino acid sequence is partially homologous to the HIV envelope glycoprotein gp120, which may explain, in part, the pathogenesis of AIDS dementia complex.
Platelet-Derived Growth Factor - Mitogenic peptide growth hormone carried in the alpha-granules of platelets. It is released when platelets adhere to traumatized tissues. Connective tissue cells near the traumatized region respond by initiating the process of replication.
Transforming Growth Factors - Hormonally active polypeptides that can induce the transformed phenotype when added to normal, non-transformed cells. They have been found in culture fluids from retrovirally transformed cells and in tumor-derived cells as well as in non-neoplastic sources. Their transforming activities are due to the simultaneous action of two otherwise unrelated factors, TRANSFORMING GROWTH FACTOR ALPHA and TRANSFORMING GROWTH FACTOR BETA.

Intercellular Signaling Peptides and Proteins Definitions and Terms

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