Fibronectin Protein, Human

Fibronectin is a glycoprotein located in the extracellular matrix that can bind to collagen, fibrin, heparin, DNA, and actin. Fibronectin is involved in cell adhesion, movement, conditioning, wound healing, and maintaining cell shape. Additionally, by binding to the LILRB4 receptor, Fibronectin can inhibit monocyte activation mediated by FCGR1A/CD64, thereby exerting immune regulatory effects. Human Fibronectin is a recombinant protein dimer complex with a full length of 573 amino acids (P1270-S1546 & A1721-T2016), expressed in E. coli and is untagged^{[1][2][3][4][5][6][7][8][9][10][11][12]}.

Fibronectin is a glycoprotein in the extracellular matrix that plays a role in cell adhesion, wound healing, embryonic development, and immune regulation. Wound healing involves the inflammatory phase, proliferative phase (granulation tissue formation), and remodeling phase. Excessive or abnormal deposition of Fibronectin after injury can lead to diseases such as fibrosis or atherosclerosis. Fibronectin plays a critical role in wound healing, involving initial repair, cell migration, tissue remodeling, and the final stages of healing^[1].
(1) Inflammatory Phase: Fibronectin expression is upregulated in response to TGF-β stimulation and binds to integrins on platelets, promoting clot formation and initial cell adhesion. The activation of integrins enhances the accumulation of Fibronectin at the wound site and promotes platelet adhesion and the release of clotting factors^[2].
(2) Proliferative Phase: Fibronectin binds to integrins (e.g., α5β1 integrin) and activates β-catenin, facilitating cell adhesion, migration, and proliferation^[3].
(3) Remodeling Phase: The degradation and remodeling of Fibronectin depend on MMPs (matrix metalloproteinases) and TIMPs (tissue inhibitors of metalloproteinases) signaling pathways. MMPs degrade Fibronectin in the provisional ECM matrix, while TIMPs inhibit MMP activity to ensure proper ECM remodeling^[4].
(4) Healing: Fibronectin binds to integrins (e.g., α5β1 integrin) to promote cell apoptosis and vascular reconstruction. TGF-β regulates Fibronectin expression to reduce excessive fibrosis and scarring^[5]. Fibronectin also supports new vessel formation and repair during vascular wound healing, with increased Fibronectin promoting endothelial cell proliferation and capillary ingrowth^[6].
Elevated Fibronectin expression may also be associated with tumor formation. The mRNA splicing of the ED-A segment of Fibronectin is dysregulated in human liver tumor tissues and is closely related to portal vein tumor thrombosis (PVTT) formation and intrahepatic tumor metastasis^[7].
Fibronectin can bind with Anastellin to form Fibronectin polymers, known as Superfibronectin, which has enhanced adhesive properties. Superfibronectin can inhibit tumor growth, angiogenesis, and metastasis. Anastellin activates p38 MAPK and inhibits lysolipid signaling^[8].
Fibronectin also inhibits monocyte activation and exerts immune regulatory effects. Fibronectin protein (Rat) (92.1% similarity to human Fibronectin protein) has been found to have effective anti-inflammatory effects in a chronic nephritis Wistar rat model^[9][10].

Fibronectin protein (Human) (2-40 nM, 24-100 h) dose-dependently promotes the growth of mouse embryonic cells lacking endogenous fibronectin^[11].
Fibronectin protein (Human) has high binding affinity for the human LILRB4 receptor and its direct homolog gp49B receptor in mice, with K_D values of 421 nM and 50.1 nM, respectively^[12].

FN30-Fc is a recombinant protein formed by fusing the N-terminal 30 kDa fragment of human fibronectin (FN30) with mouse IgG2a Fc. FN30-Fc (200 μg, intraperitoneally injected into 10-week-old mice, a total of 2 doses with a 2-week interval) shows efficacy in improving autoimmune nephritis in the BXSB/Yaa lupus (SLE) mouse model^[12].

1.Measured by its ability to support cell attachment and spreading when used as a substratum for cell culture. The ED₅₀ for this effect is ≤ 385.7 ng/mL.
2.Measured by the ability of the immobilized protein to support the adhesion of B16-F1 mouse melanoma cells. The ED₅₀ for this effect is ≤182.9 ng/mL, corresponding to a specific activity is ≥5.467×10³ units/mg.

• 
  Measured by the ability of the immobilized protein to support the adhesion of B16-F1 mouse melanoma cells. The ED₅₀ for this effect is 124.5 ng/mL, corresponding to a specific activity is 8.03×10³ units/mg.

Human

E. coli

Tag Free

P02751-1 (P1270-S1546 & A1721-T2016)

2335  [NCBI]

PTDLRFTNIGPDTMRVTWAPPPSIDLTNFLVRYSPVKNEEDVAELSISPSDNAVVLTNLLPGTEYVVSVSSVYEQHESTPLRGRQKTGLDSPTGIDFSDITANSFTVHWIAPRATITGYRIRHHPEHFSGRPREDRVPHSRNSITLTNLTPGTEYVVSIVALNGREESPLLIGQQSTVSDVPRDLEVVAATPTSLLISWDAPAVTVRYYRITYGETGGNSPVQEFTVPGSKSTATISGLKPGVDYTITVYAVTGRGDSPASSKPISINYRTEIDKPS&AIPAPTDLKFTQVTPTSLSAQWTPPNVQLTGYRVRVTPKEKTGPMKEINLAPDSSSVVVSGLMVATKYEVSVYALKDTLTSRPAQGVVTTLENVSPPRRARVTDATETTITISWRTKTETITGFQVDAVPANGQTPIQRTIKPDVRSYTITGLQPGTDYKIYLYTLNDNARSSPVVIDASTAIDAPSNLRFLATTPNSLLVSWQPPRARITGYIIKYEKPGSPPREVVPRPRPGVTEATITGLEPGTEYTIYVIALKNNQKSEPLIGRKKTDELPQLVTLPHPNLHGPEILDVPST

Approximately 56-76 kDa due to the glycosylation.

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

Lyophilized powder

Lyophilized from a 0.2 μm filtered solution of 12.5 mM Sodium Citrate, 1.25% Sucrose, pH 5.5 or PBS, pH 6.8, 5% trehalose, 5% mannitol and 0.01% Tween 80.

<0.01 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.

• [1]. Patten J, Wang K. Fibronectin in development and wound healing. Adv Drug Deliv Rev. 2021 Mar;170:353-368.  [Content Brief]

  [2]. Lenselink EA. Role of fibronectin in normal wound healing. Int Wound J. 2015 Jun;12(3):313-6. doi: 10.1111/iwj.12109. Epub 2013 Jun 7.  [Content Brief]

  [3]. Bielefeld K A, et al. Fibronectin and β-catenin act in a regulatory loop in dermal fibroblasts to modulate cutaneous healing[J]. Journal of Biological Chemistry, 2011, 286(31): 27687-27697.  [Content Brief]

  [4]. Shi F, et al. MT1-MMP regulates the turnover and endocytosis of extracellular matrix fibronectin[J]. Journal of cell science, 2011, 124(23): 4039-4050.  [Content Brief]

  [5]. Lefcort F, et al. Regulation of expression of fibronectin and its receptor, α5β1, during development and regeneration of peripheral nerve[J]. Development, 1992, 116(3): 767-782.

  [6]. Clark RA, et al. Blood vessel fibronectin increases in conjunction with endothelial cell proliferation and capillary ingrowth during wound healing. J Invest Dermatol. 1982 Nov;79(5):269-76.  [Content Brief]

  [7]. Oyama F, et al. Deregulation of alternative splicing of fibronectin pre-mRNA in malignant human liver tumors. J Biol Chem. 1989 Jun 25;264(18):10331-4.  [Content Brief]

  [8]. Yi M, Ruoslahti E. A fibronectin fragment inhibits tumor growth, angiogenesis, and metastasis. Proc Natl Acad Sci U S A. 2001 Jan 16;98(2):620-4.  [Content Brief]

  [9]. Quirós J, et al. Beneficial effect of fibronectin administration on chronic nephritis in rats. Arthritis Rheum. 1990 May;33(5):685-92.  [Content Brief]

  [10]. Su MT, et al. Blockade of checkpoint ILT3/LILRB4/gp49B binding to fibronectin ameliorates autoimmune disease in BXSB/Yaa mice. Int Immunol. 2021 Jul 23;33(8):447-458.  [Content Brief]

  [11]. Sottile J, et al. Fibronectin matrix assembly enhances adhesion-dependent cell growth. J Cell Sci. 1998 Oct;111 ( Pt 19):2933-43.  [Content Brief]