Animal-Free Fas Ligand Protein, Human (His)

Fas Ligand (CD178; APTL) is a ligand to TNFRSF6/FAS/CD95, transduces the apoptotic signal to regulate cytotoxic T-cell-mediated apoptosis, natural killer cell-mediated apoptosis and in T-cell development^[1]. Human Fas Ligand exhibits 4 isoforms, the soluble form (130-281 a.a.) of which plays an important role in the activation-induced cell death (AICD) of T lymphocytes Jurkat cells^[3]. However the membrane-bound isoform could be responsible for its inflammatory activity^[4]. Animal-Free Fas Ligand Protein, Human (His) has a total length of 152 amino acids (Q130-L281), is expressed in E. coli with N-terminal His-tag.

Fas Ligand (FasL; FASLG; CD95L), is a ligand for TNFRSF6/FAS belonging to the tumor necrosis factor (TNF). FasL is a type II transmembrane protein, riggering apoptosis of lymphocytes^[1].
FasL is expressed on a variety of cell types, including T cells, natural killer (NK) cells, monocytes, neutrophils, breast epithelial cells, and vascular endothelial cells^[2].
FasL exerts different biological activity by cleaved into 4 isoforms including membrane form, soluble form, ADAM10-processed FasL form (APL) and SPPL2A-processed FasL form (SPA). Among them, the membrane-bound form and a soluble form generated by proteolytic action of matrix metalloproteinases (MMP)^[2].
FasL or soluble FasL binding to Fas results in receptor aggregation and in the interaction of a protein called Fas-associated death domain with the Fas cytoplasmic tail. The interaction triggers a cascade of intracellular events, including the activation of the IL-1-converting enzyme-like cysteine protease (caspase 8), that ultimately leads to nucleoprotein cleavage, DNA fragmentation, and cell apoptosis^[5].
The loss of function due to mutations in murine FasL, murine Fas, human Fas, or human FasL leads to lymphoproliferation, lymphadenopathy, and autoimmune diseases^[1][3].
Meanwhile, defective activation-induced cell death (AICD) results in spontaneous mutation of Fas and FasL genes in mice with lupus-like autoimmune disease^[3].
Human Fas Ligand also involves in Jurkat cell apoptosis and binds TNFRSF6B/DcR3 to bolck apoptosis, which is a decoy receptor of apoptosis termination^[2].
FasL is widely found in different animals, while the sequence in Human is different from Rat and Mouse with similarity of 77.26% and 78.06%, respectively.

Human soluble FasL (4 units/mL; 18 hr) induces neutrophil infiltration^[4].
Human membrane-bound FasL (4 units/mL; 18 hr) is found to induce IL-1β release in plastic adherent macrophages separated from 4-day PEC instead of recombinant mouse soluble FasL (WX1)^[4].
Soluble FasL (.1-1 nM) of human induces chemotaxis of mouse neutrophils in vitro at concentrations incapable of inducing cell apoptosis.^[6].

Purified human soluble FasL (-1 ng; i.p.; single dose) does not show neutrophil chemotactic activity in vivo in ddY mice^[4].
Expressing membrane-bound FasL (FFL, FDC2) but not soluble FasL (FFS) rejects tumor cells quickly than the control in wild-type mice^[4].

Measure by its ability to induce apoptosis in Jurkat cells. The ED₅₀ for this effect is <1 ng/mL. The specific activity of recombinant human FasL is >1 x 10⁶ IU/mg

Human

E. coli

N-His

P48023 (Q130-L281)

356  [NCBI]

QIGHPSPPPEKKELRKVAHLTGKSNSRSMPLEWEDTYGIVLLSGVKYKKGGLVINETGLYFVYSKVYFRGQSCNNLPLSHKVYMRNSKYPQDLVMMEGKMMSYCTTGQMWARSSYLGAVFNLTSADHLYVNVSELSLVNFEESQTFFGLYKL

Approximately 17.31 kDa

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

Lyophilized powder

Lyophilized from a solution containing 1X PBS, pH 8.0, trehalose.

<0.1 EU per 1 μg of the protein by the LAL method.

It is not recommended to reconstitute to a concentration less than 100 μg/mL in ddH₂O.

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.

• [1]. Schneider P, et al. Characterization of Fas (Apo-1, CD95)-Fas ligand interaction. J Biol Chem. 1997 Jul 25;272(30):18827-33.  [Content Brief]

  [2]. Liu W, et al. Crystal Structure of the Complex of Human FasL and Its Decoy Receptor DcR3. Structure. 2016 Nov 1;24(11):2016-2023.  [Content Brief]

  [3]. Martínez-Lorenzo MJ, et al. Release of preformed Fas ligand in soluble form is the major factor for activation-induced death of Jurkat T cells. Immunology. 1996 Dec;89(4):511-7.  [Content Brief]

  [4]. Shudo K, et al. The membrane-bound but not the soluble form of human Fas ligand is responsible for its inflammatory activity. Eur J Immunol. 2001 Aug;31(8):2504-11.  [Content Brief]

  [5]. Puppo F, et al. Fas, Fas ligand, and transfusion immunomodulation. Transfusion. 2001 Mar;41(3):416-8.  [Content Brief]

  [6]. Ottonello L, et al. Soluble Fas ligand is chemotactic for human neutrophilic polymorphonuclear leukocytes. J Immunol. 1999 Mar 15;162(6):3601-6.  [Content Brief]