Bao Han, Liu Yuantao, Duan Yanwei, Chen Lei, Yang Qing
School of Bioengineering, Dalian University of Technology, Dalian, 116024, China.
Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China.
Insect Sci. 2025 Jun;32(3):821-832. doi: 10.1111/1744-7917.13443. Epub 2024 Sep 5.
The insect cuticle, which serves as both a protective barrier and an efficient lever system for locomotion, is an extracellular matrix primarily composed of chitin and protein. The cuticle protein CPCFC characterized by a "CFC" motif containing 2 Cys split by the insertion of 5 residues is distributed across most insect species and specifically localized in the hard part of the cuticle. However, their physiological function is not fully understood. Here, we report 2 CPCFC proteins, TcCPCFC1 and TcCPCFC2, derived from the Coleopteran insect Tribolium castaneum. We revealed that TcCPCFC1 and TcCPCFC2 were predominantly expressed during the larval and adult stages of T. castaneum, respectively. The transcription downregulation of TcCPCFC1 significantly decreased the modulus and toughness of the elytral cuticle. We found that TcCPCFC proteins have high binding affinity to chitin. We cloned and produced recombinant TcCPCFC proteins and demonstrated that the addition of TcCPCFC proteins to chitin hydrogel greatly enhanced the hydrogel's modulus and toughness by forming denser chitin fibrous networks. Our findings reveal the functional role of CPCFC proteins in enhancing mechanical properties of insect cuticle, and we validate this process in vitro, and offer a protein candidate for fabrication of advanced chitin-based materials.
昆虫表皮既是一种保护屏障，也是一种用于运动的高效杠杆系统，它是一种主要由几丁质和蛋白质组成的细胞外基质。以含有2个半胱氨酸且被5个残基插入分隔的“CFC”基序为特征的表皮蛋白CPCFC分布于大多数昆虫物种中，并特异性地定位于表皮的坚硬部分。然而，它们的生理功能尚未完全了解。在此，我们报道了源自鞘翅目昆虫赤拟谷盗的2种CPCFC蛋白，即TcCPCFC1和TcCPCFC2。我们发现，TcCPCFC1和TcCPCFC2分别在赤拟谷盗的幼虫期和成虫期大量表达。TcCPCFC1的转录下调显著降低了鞘翅表皮的模量和韧性。我们发现，TcCPCFC蛋白与几丁质具有高结合亲和力。我们克隆并制备了重组TcCPCFC蛋白，并证明将TcCPCFC蛋白添加到几丁质水凝胶中可通过形成更致密的几丁质纤维网络极大地提高水凝胶的模量和韧性。我们的研究结果揭示了CPCFC蛋白在增强昆虫表皮机械性能方面的功能作用，并且我们在体外验证了这一过程，还为先进几丁质基材料的制备提供了一种蛋白质候选物。
