Transcript levels of thymosin β4, an actin-sequestering peptide, in cell proliferation

Otero, Alejandro González; Bustelo, Xosé R.; Pichel, José G.; Freire, Manuel; Gómez-Márquez, Jaime

doi:10.1016/0167-4889(93)90177-q

Cited by 19 publications

(4 citation statements)

References 23 publications

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“…Concanavalin A stimulation of thymocytes from the glands of 6to 9-week-old rats caused a 6to 10-fold increase in TP4 in one hour (well before S phase), due to increased synthesis without a change in its mRNA (49). On the other hand, ConA, PMA or A-23 187 treatment of splenic thymocytes caused an increase in TP4 mRNA (50). These studies show that the level of TP4 or its mRNA can be significantly and rapidly altered by external stimuli.…”

Section: Changes In Beta Thymosin Mrna or Protein Levels In Tissues Omentioning

confidence: 93%

Beta thymosins as actin binding peptides

Safer¹,

Nachmias²

1994

BioEssays

114

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The beta thymosins are a highly conserved family of strongly polar 5 kDa polypeptides that are widely distributed among vertebrate classes; most are now known to bind to monomeric actin and inhibit its polymerization. One beta thymosin, beta four, (T beta 4) is the predominant form in mammalian cells, present at up to 0.5 mM. Many species are known to produce at least two beta thymosin isoforms, in some cases in the same cell. Their expression can be separately regulated. When present outside the cell, the N-terminal tetrapeptide of beta four appears to affect cell cycle regulation; beta thymosins or smaller fragments derived from them may have additional regulatory functions. We suggest that many developmental changes in beta thymosin levels within cells and tissues may be related to changes in G-actin pool size.

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Section: Changes In Beta Thymosin Mrna or Protein Levels In Tissues Omentioning

confidence: 93%

Beta thymosins as actin binding peptides

Safer¹,

Nachmias²

1994

BioEssays

114

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“…There is a 2.5‐fold increase of T β 4 during the S‐phase of thymocytes [85]. Splenic thymocytes increase T β 4 mRNA levels after stimulation with concanavalin A, phorbol 12‐myristate‐13‐acetate, or Ca 2+ ionophore [86, 87]. It has been reported that T α 1 enhances and T β 4 suppresses the mixed lymphocyte proliferative response [88].…”

Section: Roles In Immune Systemmentioning

confidence: 99%

Roles of Thymosins in Cancers and Other Organ Systems

Chen

Yang

et al. 2005

World j. surg.

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Thymosins are small peptides, originally identified from the thymus, but now known to be more widely distributed in many tissues and cells. Thymosins are divided into three main groups, alpha-, beta-, : and gamma-thymosins, based on their isoelectric points. alpha-thymosins (ProTalpha, Talphal) have nuclear localization and are involved in transcription and/or DNA replications; whereas beta-thymosins (Tbeta4, Tbeta10, Tbetal5) have cytoplasmic localization and show high affinity to G-actin for cell mobility. Furthermore, it is well known that both alpha- and beta-thymosins play important roles in modulating immune response, vascular biology, and cancer pathogenesis. More importantly, thymosins may have significant clinical applications. They may serve as molecular markers for the diagnosis and prognosis of certain diseases. In addition, they could be molecular targets of certain diseases or be used as therapeutic agents to treat certain diseases. However, the molecular mechanisms of action of thymosins are largely unknown. This review not only presents recent advances of basic science research of thymosins and their clinical applications but provides thoughtful views for future directions of investigation on thymosins.

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“…It has been identified as a major actin monomer-binding molecule [1], and may play a role in many cellular processes including motility, axonal pathfinding, differentiation, neurite formation, and proliferation [2][3][4][5][6][7][8][9][10]. The presence of Tb 4 in the mammalian nervous system, during pre-and postnatal development, is now well established [11,12].…”

Section: Introductionmentioning

confidence: 99%

The Promotive Effects of Thymosin β4 on Neuronal Survival and Neurite Outgrowth by Upregulating L1 Expression

et al. 2008

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Thymosin beta(4) (Tbeta4) is a major actin-sequestering peptide widely distributed in mammalian tissues including the nervous system. The presence of this peptide in the nervous system likely plays a role in synaptogensis, axon growth, cell migration, and plastic changes in dendritic spine. However, the effects of Tbeta4 on the survival of neurons and axonal outgrowth have still not been fully understood. So far it is not clear if the effects of Tbeta4 are associated with L1 functions. In the present study, we hypothesized that Tbeta4-induced up-regulation of L1 synthesis could be involved in the survival and axon outgrowth of cultured spinal cord neurons. To test this hypothesis, primarily cultured neurons were prepared from the mouse spinal cord and treated with various concentrations of Tbeta4 ranging from 0.1 to 10 microg/ml. The analysis of L1 mRNA expression and protein synthesis in neurons was then carried out using RT-PCR and western blot assays, respectively. After the addition of Tbeta4 to cultures, cells were then treated with antibodies against distinct domains of L1-Fc. Subsequently, beta-tubulin III and L1 double-labeled indirect immunofluorescence was carried out. Meanwhile, L1 immunofluorescent reactivity was analyzed and compared in cells treated with Tbeta4. Furthermore, the number of beta-tubulin III-positive cells and neurite lengths were measured. We found that Tbeta4 enhanced L1 expression in a dose-dependent manner, and the highest L1 mRNA and protein synthesis in cells increased by more than 2.1- and 2.3-fold in the presence of Tbeta4 at identical concentrations, respectively. Moreover, it also dose dependently enhanced neurite outgrowth and neuronal survival. Compared to conditions without Tbeta4, the length of neurite and neuronal survival increased markedly in presence of 0.5, 1, and 5 microg/ml Tbeta4, respectively, whereas the effects of Tbeta4 were significantly attenuated or inhibited in the process of L1-Fc antibodies treatment. These above results indicate that the promotive effect of Tbeta4 on the survival and neurite outgrowth of cultured spinal cord neurons might be mediated, at least in part via a stimulation of the production of L1 in the neurons.

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Transcript levels of thymosin β4, an actin-sequestering peptide, in cell proliferation

Cited by 19 publications

References 23 publications

Beta thymosins as actin binding peptides

Beta thymosins as actin binding peptides

Roles of Thymosins in Cancers and Other Organ Systems

The Promotive Effects of Thymosin β4 on Neuronal Survival and Neurite Outgrowth by Upregulating L1 Expression

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