TGF beta 1

From Wikipedia, the free encyclopedia

Transforming growth factor beta-1
Solution Structure Of TGF-β1
Other names:	TGF-beta-1
Genetic data
Locus:	Chr. 19 q13.1
Gene code:	HUGO code:TGFB1
Protein Structure/Function
Structure:	Molecular structure
Protein type:	TGF beta family
Functions:	cell differentiation, growth, cell proliferation
Other
Taxa expressing:	Homo sapiens; homologs: many metazoan phyla
Cell types:	many
Subcellular localization:	extracellular
Covalent modifications:	glycosylation
Medical/Biotechnological data
Diseases:	Camurati-Engelmann disease (CED) Mendelian Inheritance in Man (OMIM) 131300, Modifier of Cystic fibrosis
Database Links
Entrez:	7040
OMIM:	190180
RefSeq:	NM_000660
UniProt:	P01137

Transforming growth factor beta 1 or TGF-β1 is a polypeptide member of the transforming growth factor beta superfamily of cytokines. It is a secreted protein that performs many cellular functions, including the control of cell growth, cell proliferation, cell differentiation and apoptosis.

TGF-β1 was first identified in human platelets as a protein with a molecular mass of 25 kilodaltons with a potential role in wound healing.^[1] It was later characterized as a large protein precursor (containing 390 amino acids) that, was proteolytically processed to produce a mature peptide of 112 amino acids.^[2]

TGF-β1 plays and important role in controlling the immune system, and shows diiferent activities on different types of cell, or cells at different developmental stages. Most immune cells (or leukocytes) secrete TGF-β1.^[3]

Contents 1 TGF-β1 and T cells 2 TGF-β1 and B cells 3 TGF-β1 and myeloid cells 4 References

[edit] TGF-β1 and T cells

Some T cells (e.g. regulatory T cells) release TGF-β1 to inhibit the actions of other T cells. Interleukin 1- and interleukin 2-dependent proliferation of activated T cells,^[4][5] and the activation of quiescent helper T cells and cytotoxic T cells are prevented by the activity of TGF-β1.^[6][7] Similarly, TGF-β1 can inhibit the secretion and activity of many other cytokines including interferon-γ, tumor necrosis factor-alpha (TNF-α) and various interleukins. It can also decrease the expression levels of cytokine receptors, such as the IL-2 receptor to down-regulate the activity of immune cells. However, TGF-β1 can also increase the expression of certain cytokines in T cells and promote their proliferation, particularly if the cells are immature.^[8]

[edit] TGF-β1 and B cells

TGF-β1 has similar effects on B cells that also vary according to the differentiation state of the cell. It inhibits proliferation and apoptosis of B cells,^[9] and plays a role in controlling the expression of antibody, transferrin and MHC class II proteins on immature and mature B cells.^[3][9]

[edit] TGF-β1 and myeloid cells

The effects of TGF-β1 on macrophages and monocytes is predominantly suppressive; this cytokine can inhibit the proliferation of these cells and prevent their production of reactive oxygen (e.g. superoxide (O₂⁻)) and nitrogen (e.g. nitric oxide (NO)) intermediates. However, as with other cell types, TGF-β1 can also have the opposite effect on cells of myeloid origin. For example, TGF-β1 acts as a chemoattractant, directing an immune response to some pathogens; macrophages and monocytes respond to low levels of TGF-β1 in a chemotactic manner. Furthermore, the expression of monocytic cytokines (including interleukin-1(IL-1)-alpha, IL-1-beta, and TNF-α), ^[7] and phagocytic killing by macrophages can be increased by the action of TGF-β1.^[3]

[edit] References

1. ^ Assoian R, Komoriya A, Meyers C, Miller D, Sporn M (1983). "Transforming growth factor-beta in human platelets. Identification of a major storage site, purification, and characterization". J Biol Chem 258 (11): 7155-60. PMID 6602130. 
2. ^ Derynck R, Jarrett J, Chen E, Eaton D, Bell J, Assoian R, Roberts A, Sporn M, Goeddel D (1985). "Human transforming growth factor-beta complementary DNA sequence and expression in normal and transformed cells". Nature 316 (6030): 701-5. PMID 3861940. 
3. ^ ^{a b c} Letterio J, Roberts A. "Regulation of immune responses by TGF-beta". Annu Rev Immunol 16: 137-61. PMID 9597127. 
4. ^ Wahl S, Hunt D, Wong H, Dougherty S, McCartney-Francis N, Wahl L, Ellingsworth L, Schmidt J, Hall G, Roberts A (1988). "Transforming growth factor-beta is a potent immunosuppressive agent that inhibits IL-1-dependent lymphocyte proliferation". J Immunol 140 (9): 3026-32. PMID 3129508. 
5. ^ Tiemessen M, Kunzmann S, Schmidt-Weber C, Garssen J, Bruijnzeel-Koomen C, Knol E, van Hoffen E (2003). "Transforming growth factor-beta inhibits human antigen-specific CD4+ T cell proliferation without modulating the cytokine response". Int Immunol 15 (12): 1495-504. PMID 14645158. 
6. ^ Gilbert K, Thoman M, Bauche K, Pham T, Weigle W (1997). "Transforming growth factor-beta 1 induces antigen-specific unresponsiveness in naive T cells". Immunol Invest 26 (4): 459-72. PMID 9246566. 
7. ^ ^{a b} Wahl S, Wen J, Moutsopoulos N (2006). "TGF-beta: a mobile purveyor of immune privilege". Immunol Rev 213: 213-27. PMID 16972906. 
8. ^ Letterio J, Roberts A (1998). "Regulation of immune responses by TGF-beta". Annu Rev Immunol 16: 137-61. PMID 9597127. 
9. ^ ^{a b} Lebman D, Edmiston J (1999). "The role of TGF-beta in growth, differentiation, and maturation of B lymphocytes". Microbes Infect 1 (15): 1297-304. PMID 10611758.