Instituto de Investigaciones Biol�gicas (IIB)-Universidad Nacional de Mar del Plata (UNMdP)-CONICET, Funes 3250 3er nivel, Mar del Plata, Argentina.
Plant Cell Physiol. 2019 May 1;60(5):986-998. doi: 10.1093/pcp/pcz011.
Mitochondrial Nicotinamide adenine dinucleotide (NADH) dehydrogenase complex is the first complex of the mitochondrial electron transfer chain. In plants and in a variety of eukaryotes except Opisthokonta, complex I (CI) contains an extra spherical domain called carbonic anhydrase (CA) domain. This domain is thought to be composed of trimers of gamma type CA and CA-like subunits. In Arabidopsis, the CA gene family contains five members (CA1, CA2, CA3, CAL1 and CAL2). The CA domain appears to be crucial for CI assembly and is essential for normal embryogenesis. As CA and CA-like proteins are arranged in trimers to form the CA domain, it is possible for the complex to adopt different arrangements that might be tissue-specific or have specialized functions. In this work, we show that the proportion of specific CI changes in a tissue-specific manner. In immature seeds, CI assembly may be indistinctly dependent on CA1, CA2 or CA3. However, in adult plant tissues (or tissues derived from stem cells, as cell cultures), CA2-dependent CI is clearly the most abundant. This difference might account for specific physiological functions. We present evidence suggesting that CA3 does not interact with any other CA family member. As CA3 was found to interact with CI FRO1 (NDUFS4) subunit, which is located in the matrix arm, this suggests a role for CA3 in assembly and stability of CI.
线粒体烟酰胺腺嘌呤二核苷酸（NADH）脱氢酶复合体是线粒体电子传递链的第一个复合体。在植物和除了后口动物以外的各种真核生物中，复合体 I（CI）包含一个额外的球形结构域，称为碳酸酐酶（CA）结构域。这个结构域被认为是由三聚体的γ型 CA 和 CA 样亚基组成的。在拟南芥中，CA 基因家族包含五个成员（CA1、CA2、CA3、CAL1 和 CAL2）。CA 结构域似乎对 CI 组装至关重要，并且对正常胚胎发生是必需的。由于 CA 和 CA 样蛋白以三聚体的形式排列形成 CA 结构域，因此复合体可能采用不同的排列方式，这些方式可能是组织特异性的，或者具有特殊的功能。在这项工作中，我们表明，特定的 CI 比例以组织特异性的方式发生变化。在未成熟的种子中，CI 组装可能不确定地依赖于 CA1、CA2 或 CA3。然而，在成年植物组织（或由干细胞衍生的组织，如细胞培养物）中，CA2 依赖性 CI 显然是最丰富的。这种差异可能解释了特定的生理功能。我们提出的证据表明，CA3 不与任何其他 CA 家族成员相互作用。由于 CA3 被发现与位于基质臂中的 CI FRO1（NDUFS4）亚基相互作用，这表明 CA3 在 CI 的组装和稳定性中起作用。
