Thrombopoietin (Tpo), is a key regulator of megakaryocytopoiesis and thrombopoiesis. It is principally produced in the liver and is bound and internalized by the receptor Tpo R/c-mpl. Defects in the Tpo-Tpo R signaling pathway are associated with a variety of platelet disorders (1-3). Mature rat Tpo shares 68% and 81% aa sequence homology with human and mouse Tpo, respectively (4). It is an 80-85kD protein that consists of an N-terminal domain with homology to Erythropoietin (Epo) and a C-terminal domain that contains multiple Nlinked and Olinked glycosylation sites. Tpo promotes the differentiation, proliferation, and maturation of megakaryocytes (MK) and their progenitors (5-7). Several other cytokines can also promote these functions but only in cooperation with Tpo (8, 9). Notably, IL-3 independently induces MK development, although its effects are restricted to early in the MK lineage (8, 9). Tpo additionally promotes platelet production, aggregation, ECM adhesion, and activation (10-13). These actions, in combination with direct effects on cardiomyocytes, can aid in the recovery of heart function following myocardial infarction (14). Tpo is cleaved by platelet-derived thrombin following Arg191 within the C-terminal domain and subsequently at other sites upon extended digestion (15). The C-terminal domain is not required for binding to Tpo R or inducing MK growth and differentiation (6). Aside from its hematopoietic effects, Tpo is expressed in the brain where it promotes the apoptosis of hypoxia-sensitized neurons and inhibits neuronal differentiation by blocking NGF-induced signaling (16, 17).
Source:Recombinant protein corresponding to aa22-326, Ser22-Ser326, from rat Thrombopoietin, NS0-derived.
Molecular Weight:~50-66kD
Endotoxin:<0.10EU/1ug (LAL method)
Biological Activity:Measured in a cell proliferation assay using MO7e human megakaryocytic leukemic cells. Avanzi, G. et al. (1988) Br. J. Haematol. 69:359. The ED50 for this effect is 0.05-0.3ng/ml.
Storage and Stability:Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile ddH2O or PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
仕様
Size：5ug
Source Antigen：Recombinant, NSO cells
Grade：Highly Purified
Purity：~95% (SDS-PAGE)
Form：Supplied as a lyophilized powder in HCl, BSA. Reconstitute with 50ul sterile PBS (>0.1% human or BSA).
