Different Types of CA Domains Are Present in Complex I from Immature Seeds and Adult Plants in Arabidopsis thaliana

CORDOBA JUAN PABLO; SOTO DEBORA; EDUARDO JULIAN ZABALETA; MARCHETTI, MARIA FERNANDA; FASSOLARI S; PAGNUSSAT G

Ein Gedi

Conferencia; XI International Conference of Plant Mitochondrial Biology; 2019

Mitochondrial 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 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 complex I 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 complex I changes in a tissue specific manner. In immature seeds, complex I 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 complex I 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 and that may play a role in assembly and stability of complex I.