Part:BBa_K5185004

Human integrins α2 domain（α2）

The integrin α2 domain (α2) is a component of the integrin α2β1 receptor, which is pivotal in mediating cell adhesion to collagen and laminin in the extracellular matrix. By examining and manipulating the α2 domain, we can affect cellular interactions with the ECM, influencing processes like wound healing and cancer metastasis.

Other than α2, this part collection includes α1 and CBMs. This part collection of CBMs aimed to provide first aid wound dressings with enhanced antimicrobial functions and a wider and more complex application, where we characterize bacterial cellulose modification methods and constructs using CBMs as a binding domain, linking HNPs such as HNP1 and HNP4 to carbohydrates such as cellulose and chitosan. By incorporating α2 into proteins, collagen-containing and laminin-containing materials can be effective targets for modification or degradation. The part collection includes: Carbohydrate binding modules CBM2 (BBa_K4011001) and CBM3 (BBa_K4011000) which bind to cellulose, CBM5 (BBa_K5185002) which binds to chitosan, and VbCBMxx (BBa_K5185008) which binds to sodium alginate. Human integrins α1 domain (BBa_K5185003) and α2 domain (BBa_K5185004), linking functional proteins to collagen. This part collection can help to achieve modification of cellulose membranes using different modification/functionalization proteins.

Since collagen in itself promotes new skin cell growth, it could be targeted for use in wound dressings that prioritize wound recovery.

Usage and Biology

In physiological contexts, the integrin α2 domain enables cells to adhere to collagen types I, III, and IV, as well as laminin, facilitating processes such as cell motility and tissue repair. It contains a MIDAS motif essential for ligand binding. The α2 domain also transduces signals that influence cell survival and differentiation. The structure of the integrin α2 domain is documented in the Protein Data Bank (accession: 1DZI). Research on the α2 domain includes its involvement in thrombosis, cancer progression, and mechanotransduction, making it significant for developing anti-thrombotic agents and cancer therapeutics.

Source

The integrin α2 domain is derived from human cells expressing the integrin α2β1 complex.

Results

We obtained a fusion protein composed of a binding domain protein linked to a fluorescent protein, naming it α2-eforRed. Figure A shows the results of the SDS-PAGE analysis of the target fusion proteins (binding domains linked to chromoproteins). The α2-eforRed fusion protein was expressed in E. coli BL21 (DE3). α2-eforRed has a molecular weight of 49.1kDa and is successfully expressed. The color of α2-eforRed suspended in 20mM Tris-HCl under bluelight is shown in Figure B, expressing the correct color pink. α2's ability to bind with collagen is assessed, as shown in Figure C. It is important to note that the α2 binding domain is intended to interact specifically with type IV collagen. However, due to budget constraints in our lab, we assessed its binding ability using type II collagen as a substitute. The comparatively lower brightness observed in the sodium alginate and collagen mixture after washing may be ascribed to this constraint. Nevertheless, the results indicate that our α2-eforRed fusion protein can successfully bind to the collagen material, as it remains brighter than the control group.

Figure 1:

(a) SDS-PAGE identification of BDC shows the results of SDS-PAGE analysis of the target fusion proteins(BDC). All fusion proteins were expressed in E. coli BL21 (DE3), except for CBMxx-gfasPurple, which was expressed in the SHuffle T7 strain due to its low solubility in BL21 (DE3). α1-mRFP, α2-eforRed, CBM2-mTurquoise, CBM3-sfGFP, CBM5-fwYellow, and CBMxx-gfasPurple each have molecular weights of 49.2 kDa, 49.1 kDa, 40 kDa, 46kDa, 32.l kDa, and 49.5 kDa, respectively.
(b)Yellow-light detection of BDC shows the color of each fusion protein suspended in 20 mM Tris HCl under bluelight.
(c) Binding efficiencies of cellulose binding domains CBM2 and CBM3 toward cellulose gauze; binding efficiencies of collagen binding domains α1 and α2, chitosan binding domain CBM5, and alginate binding domain VbCBMxx toward respective hydrogel materials.

Reference

Armenta, S., Moreno-Mendieta, S., Sánchez-Cuapio, Z., Sánchez, S., & Rodríguez-Sanoja, R. (2017). Advances in molecular engineering of carbohydrate-binding modules. Proteins, 85(9), 1602–1617.
Han, Y., Gao, P., Yu, W., & Lu, X. (2017). Thermostability enhancement of chitosanase CsnA by fusion a family 5 carbohydrate-binding module. Biotechnology letters, 39(12), 1895–1901. https://doi.org/10.1007/s10529-017-2406-2
Heino, J., Siljamäki, E. (2023). Integrins α1β1 and α2β1: The Generalist Collagen Receptors. In: Gullberg, D., Eble, J.A. (eds) Integrins in Health and Disease. Biology of Extracellular Matrix, vol 13. Springer, Cham. https://doi.org/10.1007/978-3-031-23781-2_1
Mei, X., Tao, W., Sun, H., Liu, G., Chen, G., Zhang, Y., Xue, C., & Chang, Y. (2024). Characterization and structural identification of a novel alginate-specific carbohydrate-binding module (CBM): The founding member of a new CBM family. International journal of biological macromolecules, 277(Pt 3), 134221. https://doi.org/10.1016/j.ijbiomac.2024.134221