SDF-1 alpha/CXCL12 Protein, Human

The SDF-1 alpha/CXCL12 protein is a chemoattractant for immune cells. SDF-1 alpha/CXCL12 Protein, Human is the recombinant human-derived SDF-1 alpha/CXCL12 protein, expressed by E. coli , with tag free.

SDF-1 alpha/CXCL12 protein functions as a chemoattractant with specific activity on T-lymphocytes and monocytes, excluding neutrophils. Upon activation of the C-X-C chemokine receptor CXCR4, it induces a rapid and transient rise in intracellular calcium ions, facilitating chemotaxis. SDF-1-beta(3-72) and SDF-1-alpha(3-67) exhibit reduced chemotactic activity, and binding to cell surface proteoglycans appears to inhibit the formation of SDF-1-alpha(3-67), preserving activity at local sites. Additionally, it binds to the atypical chemokine receptor ACKR3, activating the beta-arrestin pathway and serving as a scavenger receptor for SDF-1. Through binding to the allosteric site (site 2) of integrins, it activates ITGAV:ITGB3, ITGA4:ITGB1, and ITGA5:ITGB1 independently of CXCR4. Acting as a positive regulator of monocyte migration and a negative regulator of monocyte adhesion via the LYN kinase, SDF-1 alpha/CXCL12 stimulates migration of monocytes and T-lymphocytes through CXCR4 and ACKR3, decreasing monocyte adherence to ICAM-1-coated surfaces, a ligand for beta-2 integrins. The SDF1A/CXCR4 signaling axis inhibits beta-2 integrin LFA-1-mediated adhesion of monocytes to ICAM-1 through LYN kinase. It inhibits CXCR4-mediated infection by T-cell line-adapted HIV-1, plays a protective role after myocardial infarction, and induces down-regulation and internalization of ACKR3 in various cells. Essential during embryonic development, it is required for B-cell lymphopoiesis, myelopoiesis in bone marrow, and heart ventricular septum formation. Furthermore, SDF-1 alpha/CXCL12 stimulates the proliferation of bone marrow-derived B-cell progenitors in the presence of IL7, as well as the growth of stromal cell-dependent pre-B-cells (By similarity). Existing in monomeric or homodimeric forms, the equilibrium is influenced by non-acidic pH, multivalent anions, and binding to CXCR4 or heparin. The monomeric form is vital for full chemotactic activity and resistance to ischemia/reperfusion injury, while the dimeric form acts as a partial agonist of CXCR4, stimulating Ca2+ mobilization without chemotactic activity, serving instead as a selective antagonist that blocks chemotaxis induced by the monomeric form. SDF-1 alpha/CXCL12 interacts with the N-terminus of ACKR3, integrin subunit ITGB3 (via the allosteric site (site 2)), and TNFAIP6 via the Link domain.

1. Full biological activity determined by a chemotaxis bioassay using PHA and rHuIL-2 activated human peripheral blood T-lymphocytes is in a concentration range of 20-80 ng/mL.
2. Measured by its ability to chemoattract IL-2-activated human T cells. The ED₅₀ for this effect is approximately ≤45.17 ng/mL, corresponding to a specific activity is ≥2.214×10⁴ U/mg.

Human

E. coli

Tag Free

P48061-2 (K22-K89)

6387  [NCBI]

KPVSLSYRCPCRFFESHVARANVKHLKILNTPNCALQIVARLKNNNRQVCIDPKLKWIQEYLEKALNK

Approximately 8-10.0 kDa

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  Greater than 95% as determined by reducing SDS-PAGE.

Lyophilized powder

Lyophilized from a 0.2 μm filtered solution of 20 mM PB, 150 mM NaCl, pH 7.4 or 20 mM PB, 130 mM NaCl, pH 7.3.

<1 EU/μg, determined by LAL method.

It is not recommended to reconstitute to a concentration less than 100 μg/mL in ddH₂O. For long term storage it is recommended to add a carrier protein (0.1% BSA, 5% HSA, 10% FBS or 5% Trehalose).

Stored at -20°C for 2 years. After reconstitution, it is stable at 4°C for 1 week or -20°C for longer (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.

Room temperature in continental US; may vary elsewhere.