Thymosin - Revision history

Bradley Monk at 16:43, 15 December 2016

2016-12-15T16:43:32Z

← Older revision		Revision as of 09:43, 15 December 2016
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	Thymosin β<sub>4</sub> is a member of the Beta thymosin family of proteins which have in common a sequence of about 40 amino acids (see: [https://en.wikipedia.org/wiki/Beta_thymosins Beta Thymosins]). Found almost exclusively in multicellular animals, Thymosin β<sub>4</sub> was originally obtained from the thymus, along with in company with several other small proteins.		Thymosin β<sub>4</sub> is a member of the Beta thymosin family of proteins which have in common a sequence of about 40 amino acids (see: [https://en.wikipedia.org/wiki/Beta_thymosins Beta Thymosins]). Found almost exclusively in multicellular animals, Thymosin β<sub>4</sub> was originally obtained from the thymus, along with in company with several other small proteins.

	See also: [[Actin]]		<big>'''See also: [[Actin]] and [[Actin Dynamics]]'''</big>

	=== Relation to the WH2 sequence module ===		=== Relation to the WH2 sequence module ===

Bradley Monk at 18:56, 2 October 2016

2016-10-02T18:56:00Z

← Older revision		Revision as of 11:56, 2 October 2016
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	Thymosin beta-4 (aliases: '''Thymosin β4, Tβ4, β-Thymosin, TMSB4X, FX, PTMB4, TB4X, TMSB4''') is a protein that in humans is encoded by the TMSB4X gene (there is also a Y-chromosome copy: TMSB4Y). Thymosin β4 has a molecular weight of 4921 g/mol and the protein consists of 43 amino acids:		Thymosin beta-4 (aliases: '''Thymosin β4, Tβ4, β-Thymosin, TMSB4X, FX, PTMB4, TB4X, TMSB4''') is a protein that in humans is encoded by the TMSB4X gene (on the X-chromosome; there is also a suppressed Y-chromosome copy: TMSB4Y). Thymosin β4 has a molecular weight of 4921 g/mol and the protein consists of 43 amino acids:

	* MSDKPDMAEI EKFDKSKLKK TETQEKNPLP SKETIEQEKQ AGES		* MSDKPDMAEI EKFDKSKLKK TETQEKNPLP SKETIEQEKQ AGES

Bradley Monk at 13:06, 2 October 2016

2016-10-02T13:06:33Z

← Older revision		Revision as of 06:06, 2 October 2016
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	Thymosin β<sub>4</sub> is a member of the Beta thymosin family of proteins which have in common a sequence of about 40 amino acids (see: [https://en.wikipedia.org/wiki/Beta_thymosins Beta Thymosins]). Found almost exclusively in multicellular animals, Thymosin β<sub>4</sub> was originally obtained from the thymus, along with in company with several other small proteins.		Thymosin β<sub>4</sub> is a member of the Beta thymosin family of proteins which have in common a sequence of about 40 amino acids (see: [https://en.wikipedia.org/wiki/Beta_thymosins Beta Thymosins]). Found almost exclusively in multicellular animals, Thymosin β<sub>4</sub> was originally obtained from the thymus, along with in company with several other small proteins.

			See also: [[Actin]]

	=== Relation to the WH2 sequence module ===		=== Relation to the WH2 sequence module ===
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	~~See also: [[Actin]]~~		==Articles==
	<!-- {{Article\|xxxxAUTHORSxxxx\|YEAR\|JOURNAL • [http://articlelink.com FullText]\|18341992\|xxxxTITLE.}} -->		<!-- {{Article\|xxxxAUTHORSxxxx\|YEAR\|JOURNAL • [http://articlelink.com FullText]\|18341992\|xxxxTITLE.}} -->

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	~~==Articles==~~		{{Article\|Roy, et al. Jacobson\|2001\|J Cell Biol • [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2174335/ FullText]\|PMC2174335\|Local Photorelease of Caged Thymosin β4 in Locomoting Keratocytes Causes Cell Turning.}}

			The broad aim of this work was to explore the feasibility of using light-directed perturbation techniques to study cell locomotion. Specifically, a caged form of thymosin β4 (Tβ4) was photoactivated in a defined local region of locomoting fish scale keratocytes and the resulting perturbation of locomotion was studied. Purified Tβ4 was produced in an inactive form by “caging” with ([n-nitroveratryl]oxy)chlorocarbamate. In vitro spectrophotofluorometric assays indicated that caged Tβ4 did not change the normal actin polymerization kinetics, whereas photoactivated Tβ4 significantly inhibited actin polymerization. With an a priori knowledge of the cytoplasmic diffusion coefficient of Tβ4 as measured by fluorescence recovery after photobleaching experiments, the rapid sequestration of actin monomers by uncaged Tβ4 and the consequent reduction in the diffusional spread of the Tβ4–actin complex were predicted using Virtual Cell software (developed at the Center for Biomedical Imaging Technology, University of Connecticut Health Center). These simulations demonstrated that locally photoactivating Tβ4 in keratocytes could potentially elicit a regional locomotory response. Indeed, when caged Tβ4 was locally photoactivated at the wings of locomoting keratocytes, specific turning about the irradiated region was observed, whereas various controls were negative. Additionally, loading of exogenous Tβ4 into both keratocytes and fibroblasts caused very rapid disassembly of actin filaments and reduction of cellular contractility. Based on these results, a mechanical model is proposed for the turning behavior of keratocytes in response to photoreleased Tβ4.












	<!-- * {{PopFig\|[[File:Dot.png]]\|<html><video src="XXXXXX" controls></video> <br> <div style='color:white; width:400px'> XXXXX </div></html>\|\|<big>SI video1 </big>}} -->		<!-- * {{PopFig\|[[File:Dot.png]]\|<html><video src="XXXXXX" controls></video> <br> <div style='color:white; width:400px'> XXXXX </div></html>\|\|<big>SI video1 </big>}} -->

Bradley Monk at 12:29, 2 October 2016

2016-10-02T12:29:36Z

← Older revision		Revision as of 05:29, 2 October 2016
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	Thymosin beta-4 (aliases: '''Thymosin β4, Tβ4, β-Thymosin, TMSB4X, FX, PTMB4, TB4X, TMSB4''') is a protein that in humans is encoded by the TMSB4X gene (~~can~~ also ~~be encoded by the~~ TMSB4Y ~~gene??~~). Thymosin β4 has a molecular weight of 4921 g/mol and the protein consists of 43 amino acids:		Thymosin beta-4 (aliases: '''Thymosin β4, Tβ4, β-Thymosin, TMSB4X, FX, PTMB4, TB4X, TMSB4''') is a protein that in humans is encoded by the TMSB4X gene (there is also a Y-chromosome copy: TMSB4Y). Thymosin β4 has a molecular weight of 4921 g/mol and the protein consists of 43 amino acids:

	* MSDKPDMAEI EKFDKSKLKK TETQEKNPLP SKETIEQEKQ AGES		* MSDKPDMAEI EKFDKSKLKK TETQEKNPLP SKETIEQEKQ AGES

Bradley Monk at 12:27, 2 October 2016

2016-10-02T12:27:34Z

← Older revision		Revision as of 05:27, 2 October 2016
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			Thymosin beta-4 (aliases: '''Thymosin β4, Tβ4, β-Thymosin, TMSB4X, FX, PTMB4, TB4X, TMSB4''') is a protein that in humans is encoded by the TMSB4X gene (can also be encoded by the TMSB4Y gene??). Thymosin β4 has a molecular weight of 4921 g/mol and the protein consists of 43 amino acids:

			* MSDKPDMAEI EKFDKSKLKK TETQEKNPLP SKETIEQEKQ AGES



			Thymosin β<sub>4</sub> is a member of the Beta thymosin family of proteins which have in common a sequence of about 40 amino acids (see: [https://en.wikipedia.org/wiki/Beta_thymosins Beta Thymosins]). Found almost exclusively in multicellular animals, Thymosin β<sub>4</sub> was originally obtained from the thymus, along with in company with several other small proteins.


			=== Relation to the WH2 sequence module ===

			The N-terminal half of β-thymosins bears a strong similarity in amino acid sequence to a very widely distributed sequence module, the WH2 module. (Wasp Homology Domain 2 - the name is derived from Wiskott-Aldrich syndrome protein). Evidence from X-ray crystallography shows that this part of β-thymosins binds to actin in a near-identical manner to that of WH2 modules, both adopting as they bind, a conformation which has been referred to as the β-thymosin/WH2 fold. β-thymosins may therefore have evolved by addition of novel C-terminal sequence to an ancestral WH2 module. However, sequence similarity searches designed to identify present-day WH2 domains fail to recognise β-thymosins, (and vice versa) and the sequence and functional similarities may result from convergent evolution.

			=== Biological activities of thymosin β4 ===
			The archetypical β-thymosin is β4 (product in humans of the TMSB4X gene), which is a major cellular constituent in many tissues. Its intracellular concentration may reach as high as 0.5 mM. Following Thymosin α1, β4 was the second of the biologically active peptides from Thymosin Fraction 5 to be completely sequenced and synthesized. Any concepts of the biological role of thymosin β4 must inevitably be coloured by the demonstration that total ablation of the thymosin β4 gene in the mouse allows apparently normal embryonic development of mice which are fertile as adults.


			=== Actin binding ===
			Thymosin β4 was initially perceived as a thymic hormone. However this changed when it was discovered that it forms a 1:1 complex with G (globular) actin, and is present at high concentration in a wide range of mammalian cell types. When appropriate, G-actin monomers polymerize to form F (filamentous) actin, which, together with other proteins that bind to actin, comprise cellular microfilaments. Formation by G-actin of the complex with β-thymosin (= "sequestration") opposes this. Due to its profusion in the cytosol and its ability to bind G-actin but not F-actin, thymosin β4 is regarded as the principal actin-sequestering protein in many cell types. Thymosin β4 functions like a buffer for monomeric actin as represented in the following reaction:

			Factin ↔ Gactin + Thymosinβ4 ↔ Gactin:Thymosinβ4

			Release of G-actin monomers from thymosin β4 occurs as part of the mechanism that drives actin polymerization in the normal function of the cytoskeleton in cell morphology and cell motility. The sequence <code>LKKTET</code>, which starts at residue 17 of the 43-amino acid sequence of thymosin beta-4, and is strongly conserved between all β-thymosins, together with a similar sequence in WH2 domains, is frequently referred to as "the actin-binding motif" of these proteins, although modelling based on X-ray crystallography has shown that essentially the entire length of the β-thymosin sequence interacts with actin in the actin-thymosin complex.







	See also: [[Actin]]		See also: [[Actin]]
	<!-- {{Article\|xxxxAUTHORSxxxx\|YEAR\|JOURNAL • [http://articlelink.com FullText]\|18341992\|xxxxTITLE.}} -->		<!-- {{Article\|xxxxAUTHORSxxxx\|YEAR\|JOURNAL • [http://articlelink.com FullText]\|18341992\|xxxxTITLE.}} -->

Bradley Monk at 11:58, 2 October 2016

2016-10-02T11:58:07Z

← Older revision		Revision as of 04:58, 2 October 2016
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	See also: [[Actin]]		See also: [[Actin]]
			<!-- {{Article\|xxxxAUTHORSxxxx\|YEAR\|JOURNAL • [http://articlelink.com FullText]\|18341992\|xxxxTITLE.}} -->

			{{Article\|van Kesteren, et al., Smit\|2006\|JNeuro • [https://www.ncbi.nlm.nih.gov/pubmed/16399682 FullText]\|16399682\|Local Synthesis of Actin-Binding Protein β-Thymosin Regulates Neurite Outgrowth.}}

			Local protein synthesis plays an essential role in the regulation of various aspects of axonal and dendritic function in adult neurons. At present, however, there is no direct evidence that local protein translation is functionally contributing to neuronal outgrowth. Here, we identified the mRNA encoding the actin-binding protein β-thymosin as one of the most abundant transcripts in neurites of outgrowing neurons in culture. β-Thymosin mRNA is not evenly distributed in neurites, but appears to accumulate at distinct sites such as turning points and growth cones. Using double-stranded RNA knockdown, we show that reducing β-thymosin mRNA levels results in a significant increase in neurite outgrowth, both in neurites of intact cells and in isolated neurites. Together, our data demonstrate that local synthesis of β-thymosin is functionally involved in regulating neuronal outgrowth.

Bradley Monk at 11:46, 2 October 2016

2016-10-02T11:46:00Z

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Bradley Monk: Created page with "See also: Actin"

2016-10-02T11:44:38Z

Created page with "See also: Actin"

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