Dataset Information

Overlapping Functions of the Paralogous Proteins AtPAP2 and AtPAP9 in Arabidopsis thaliana.

ABSTRACT: Arabidopsis thaliana purple acid phosphatase 2 (AtPAP2), which is anchored to the outer membranes of chloroplasts and mitochondria, affects carbon metabolism by modulating the import of some preproteins into chloroplasts and mitochondria. AtPAP9 bears a 72% amino acid sequence identity with AtPAP2, and both proteins carry a hydrophobic motif at their C-termini. Here, we show that AtPAP9 is a tail-anchored protein targeted to the outer membrane of chloroplasts. Yeast two-hybrid and bimolecular fluorescence complementation experiments demonstrated that both AtPAP9 and AtPAP2 bind to a small subunit of rubisco 1B (AtSSU1B) and a number of chloroplast proteins. Chloroplast import assays using [³⁵S]-labeled AtSSU1B showed that like AtPAP2, AtPAP9 also plays a role in AtSSU1B import into chloroplasts. Based on these data, we propose that AtPAP9 and AtPAP2 perform overlapping roles in modulating the import of specific proteins into chloroplasts. Most plant genomes contain only one PAP-like sequence encoding a protein with a hydrophobic motif at the C-terminus. The presence of both AtPAP2 and AtPAP9 in the Arabidopsis genome may have arisen from genome duplication in Brassicaceae. Unlike AtPAP2 overexpression lines, the AtPAP9 overexpression lines did not exhibit early-bolting or high-seed-yield phenotypes. Their differential growth phenotypes could be due to the inability of AtPAP9 to be targeted to mitochondria, as the overexpression of AtPAP2 on mitochondria enhances the capacity of mitochondria to consume reducing equivalents.

SUBMITTER: Zhang R

PROVIDER: S-EPMC8303434 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:P5B ATPases are present in the genomes of diverse unicellular and multicellular eukaryotes, indicating that they have an ancient origin, and that they are important for cellular fitness. Inactivation of ATP13A2, one of the four human P5B ATPases, leads to early-onset Parkinson's disease (Kufor-Rakeb Syndrome). The presence of an invariant PPALP motif within the putative substrate interaction pocket of transmembrane segment M4 suggests that all P5B ATPases might have similar transport specificity; however, the identity of the transport substrate(s) remains unknown. Nematodes of the genus Caenorhabditis possess three paralogous P5B ATPase genes, catp-5, catp-6 and catp-7, which probably originated from a single ancestral gene around the time of origin of the Caenorhabditid clade. By using CRISPR/Cas9, we have systematically investigated the expression patterns, subcellular localization and biological functions of each of the P5B ATPases of C. elegans. We find that each gene has a unique expression pattern, and that some tissues express more than one P5B. In some tissues where their expression patterns overlap, different P5Bs are targeted to different subcellular compartments (e.g., early endosomes vs. plasma membrane), whereas in other tissues they localize to the same compartment (plasma membrane). We observed lysosomal co-localization between CATP-6::GFP and LMP-1::RFP in transgenic animals; however, this was an artifact of the tagged LMP-1 protein, since anti-LMP-1 antibody staining of native protein revealed that LMP-1 and CATP-6::GFP occupy different compartments. The nematode P5Bs are at least partially redundant, since we observed synthetic sterility in catp-5(0); catp-6(0) and catp-6(0) catp-7(0) double mutants. The double mutants exhibit defects in distal tip cell migration that resemble those of ina-1 (alpha integrin ortholog) and vab-3 (Pax6 ortholog) mutants, suggesting that the nematode P5Bs are required for ina-1and/or vab-3 function. This is potentially a conserved regulatory interaction, since mammalian ATP13A2, alpha integrin and Pax6 are all required for proper dopaminergic neuron function.

Dataset Information

Overlapping Functions of the Paralogous Proteins AtPAP2 and AtPAP9 in Arabidopsis thaliana.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets