植物C2结构域脱落酸相关蛋白的研究进展

doi:10.13560/j.cnki.biotech.bull.1985.2025-0590

摘要/Abstract

摘要：

C2结构域蛋白（C2 domain proteins, C2DPs）是一类广泛存在于真核生物中的蛋白质，其典型特征是含有约130个氨基酸残基组成的C2结构域。植物C2结构域脱落酸相关蛋白（C2-domain abscisic acid （ABA）-related protein, CAR）属于C2DPs亚家族I，由一个C2结构域和一个植物特有的“sig”插入域组成。其中，C2结构域以Ca²⁺依赖的方式结合磷脂而介导蛋白膜定位；而“sig结构域”则使CAR蛋白可以结合不同种类的信号蛋白复合物，进而参与调控植物生长发育和逆境胁迫响应过程。本文系统综述了CAR蛋白的结构特征、组织表达模式和亚细胞定位规律，重点阐述了其在ABA信号转导、向光向重性生长、铁营养吸收、生物及非生物胁迫响应中的功能与作用机制，并对未来研究方向作出展望，以期为深入解析植物CAR蛋白的调控网络及其在作物抗逆遗传改良中的应用提供理论参考。

关键词: C2结构域蛋白, CAR蛋白, 生长发育, 逆境响应, 信号转导

Abstract:

C2 domain proteins (C2DPs) are a class of proteins widely present in eukaryotes, characterized typically by containing a C2 domain composed of approximately 130 amino acid residues. Plant C2-domain abscisic acid (ABA)-related proteins (CARs), which belong to subfamily I of C2DPs, consist of one C2 domain and a plant-specific “sig” insertion domain. The C2 domain binds to phospholipids in a Ca²⁺- dependent manner to mediate the membrane localization of proteins. The “sig domain” enables CAR proteins to bind to complexes of different types of signaling proteins, thereby participating in the regulation of plant growth and development as well as responses to stress conditions. This review systematically summarizes the structural characteristics, tissue expression patterns, and subcellular localizations of CAR proteins, with particular emphasis on their functions and mechanisms in ABA signal transduction, phototropic and gravitropic growth, iron nutrient uptake, and responses to biotic and abiotic stresses. Additionally, future research directions are proposed, aiming to provide a theoretical reference for in-depth analysis of the regulatory network of plant CAR proteins and their application for developing stress-resilient crops.

Key words: C2 domain protein, CAR protein, growth and development, stress response, signal transduction

闫琪琪, 卜芋芬, 张小欣, 马晓岑, 荆艳萍. 植物C2结构域脱落酸相关蛋白的研究进展[J]. 生物技术通报, 2026, 42(4): 17-25.

YAN Qi-qi, BU Yu-fen, ZHANG Xiao-xin, MA Xiao-cen, JING Yan-ping. Advances in the Studies of Plant C2 Domain Abscisic Acid-related Protein[J]. Biotechnology Bulletin, 2026, 42(4): 17-25.

图/表 3

图1 AtCAR4的结构

Fig. 1 Structure of AtCAR4

表1 不同植物CAR蛋白的主要功能

Table 1 Main functions of CAR proteins in different plants

蛋白名称 Protein name	物种 Species	主要功能 Major functions	参考文献 Reference
AtCAR1	拟南芥	参与ABA信号，增强ABA敏感性；负调控碱胁迫响应	［18-19， 28］
AtCAR4	拟南芥	参与ABA信号；正调控盐胁迫与生物胁迫抗性	［29-31］
AtCAR5	拟南芥	参与ABA信号	［19， 23］
AtCAR6/EHB1	拟南芥	负调控向光性与向重性；负调控铁吸收；负调控碱胁迫响应	［23， 26-28］
AtCAR9	拟南芥	参与ABA信号；正调控干旱胁迫耐受性	［19-20］
AtCAR10	拟南芥	负调控碱胁迫响应	［28］
IbCAR1	甘薯	增强盐胁迫下细胞完整性，激活ROS清除系统	［32］
OsGAP1/CAR4	水稻	增强盐胁迫与生物胁迫抗性	［30-31， 33］

图2 CAR蛋白参与的调控网络及其生物学功能a和g：LOT1蛋白与CAR蛋白在细胞核中互作，抑制CAR蛋白泛素化修饰而维持其稳定性。受到干旱胁迫或者存在ABA信号时，ABA被细胞质或细胞核（未画出）中的PYR/PYL/RCAR受体（简称PYLs）识别，触发细胞质或细胞核中Ca²⁺浓度升高，降低了CAR蛋白与LOT1蛋白之间的亲和性，促使CAR蛋白转移至细胞膜，介导ABA受体PYLs到细胞膜上，响应ABA信号，增强植物的抗旱性［19-20］；b：CAR与NPH3的BTB/POZ结构域结合，干扰了CUL3-NPH3复合体的组装及其介导的PHOT1泛素化降解，负向调控植物向光性［26］；c：CAR蛋白与ARF-GAP家族成员AGD12竞争性结合囊泡运输相关小G蛋白ARF，阻碍AGD12对ARF的GTP酶激活作用，抑制ARF正常的GTP/GDP循环，影响囊泡运输，破坏PIN蛋白的极性定位，进而影响生长素分布而对向重性产生负面影响［27］；d：CAR蛋白负调控植物铁转运蛋白IRT1，影响植物铁吸收［23］；e：CAR蛋白负调控病原体感染负调节因子YchF1，解除其抑制作用而增强植物生物胁迫抗性［29］，CAR蛋白可以增强脂筏结构稳定性，富集免疫相关蛋白，增强免疫信号，此外，与FER互作的CARs发生磷酸化，从膜上解离，维持膜上蛋白含量的动态平衡，避免免疫信号过度激活［25］；f：CAR蛋白负调控盐胁迫负调节因子YchF1，增强植物耐盐性［32］；h：CAR蛋白负调控质膜H＋-ATPase酶AHA1活性，负调控植物耐碱性［28］；红色箭头表示离子浓度上升（↑）或者下降（↓），图中①表示CAR蛋白的泛素化，②表示CAR蛋白的磷酸化

Fig. 2 Regulatory network and biological functions associated with CAR proteina & g: The LOT1 protein interacts with the CAR protein in the nucleus, inhibiting the ubiquitination modification of the CAR protein and thereby maintaining its stability. When subjected to drought stress or in the presence of ABA signaling, ABA is recognized by cytosolic or nuclear (not shown) PYR/PYL/RCAR receptors (abbreviated as PYLs). This recognition triggers an increase in cytosolic or nuclear Ca²⁺ concentration, which reduces the affinity between the CAR protein and the LOT1 protein. This promotes the relocation of the CAR protein to the plasma membrane, where it mediates the membrane recruitment of ABA receptor PYLs. This process enables the cell to respond to ABA signaling and enhances the plant’s drought resistance[19-20]; b: CAR binds to the BTB/POZ domain of NPH3, thereby impairing CUL3-NPH3 assembly, inhibiting ubiquitin-dependent degradation of PHOT1, and consequently attenuating plant phototropism[26]; c: CAR competitively inhibits ARF-GAP family members (e.g., AGD12) by binding to ADP-ribosylation factor (ARF) GTPases. This disrupts ARF GTP/GDP cycling, impairs PIN protein polar localization via vesicle trafficking defects, and compromises root gravitropism[27]; d: CAR protein negatively regulates the plant iron transporter IRT1, thereby affecting plant iron uptake[23]; e: CAR proteins negatively regulate YchF1-a negative regulator of pathogen infection-thereby relieving its inhibitory effect and enhancing plant resistance to biotic stresses[29]. Additionally, CAR proteins stabilize lipid raft structures, promoting the enrichment of immune-related proteins and strengthening immune signaling. Furthermore, CARs that interact with FER undergo phosphorylation, dissociate from the membrane, maintain the dynamic balance of membrane protein content, and prevent excessive activation of immune signaling[25]; f: CAR inhibits the salt stress negative regulator YchF1, conferring enhanced salinity tolerance[32]; h: CAR downregulates the plasma membrane H⁺-ATPase AHA1, thereby compromising plant tolerance to alkaline stress[28]. Red arrows indicate ion concentration increase (↑) or decrease (↓). Label ① marks ubiquitination of CAR, and ② indicates phosphorylation of CAR

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