LPA2 protein is involved in photosystem II assembly in Chlamydomonas reinhardtii

Abstract

Photosynthetic eukaryotes require the proper assembly of photosystem II (PSII) in order to strip electrons from water and fuel carbon fixation reactions. In Arabidopsis thaliana, one of the PSII subunits (CP43/PsbC) was suggested to be assembled into the PSII complex via its interaction with an auxiliary protein called Low PSII Accumulation 2 (LPA2). However, the original articles describing the role of LPA2 in PSII assembly have been retracted. To investigate the function of LPA2 in the model organism for green algae, Chlamydomonas reinhardtii, we generated knockout lpa2 mutants by using the CRISPR-Cas9 target-specific genome editing system. Biochemical analyses revealed the thylakoidal localization of LPA2 protein in the wild type (WT), whereas lpa2 mutants were characterized by a drastic reduction in the levels of D1, D2, CP47 and CP43 proteins. Consequently, reduced PSII supercomplex accumulation, chlorophyll content per cell, PSII quantum yield and photosynthetic oxygen evolution were measured in the lpa2 mutants, leading to the almost complete impairment of photoautotrophic growth. Pulse-chase experiments demonstrated that the absence of LPA2 protein caused reduced PSII assembly and reduced PSII turnover. Taken together, our data indicate that, in C. reinhardtii, LPA2 is required for PSII assembly and proper function.

LPAR2 correlated with different prognosis and immune cell infiltration in head and neck squamous cell carcinoma and kidney renal clear cell carcinoma

“…A few studies have suggested that LPAR2 is associated with several cancers, such as breast [ 16 , 31 , 32 ], colon [ 20 ], ovarian [ 33 ], and stomach cancers [ 17 ]. These studies have reported that LPAR2 expression is important in cancer biology and may promote gene transcription and cell proliferation in the tumor microenvironment [ 17 , 34 , 35 ]. However, the mechanism of action of LPAR2 in tumors remains unclear.…”

Molecular evolution and functional modification of plant miRNAs with CRISPR

“…The delivery of CRISPR/Cas systems into plant cells and the generation of genome-modified plants are the bottlenecks for gene editing in many plant species. Although CRISPR/Cas gene editing has been established in the green algae, V. carteri [137] and C. reinhardtii [138], in the liverwort M. polymorpha [28] (Table S4), and in the moss P. patens [99], many angiosperms, gymnosperms, and ferns that are important for evolutionary research are difficult to transform by biolistic bombardment or by Agrobacterium-mediated transformation. In addition, the high transformation efficiencies that are required for the engineering of important crops such as wheat, maize, barley, and cotton are limited to particular genotypes [22,[139][140][141], which restricts the broad use of gene editing technologies.…”

Acclimation strategies of the green alga Chlorella vulgaris to different light regimes revealed by physiologic and comparative proteomic analyses

“…HL cells also showed downregulation of Low PSII Accumulation (LPA) protein expression. These proteins are involved in PSII assembly, and gene deletions in A. thaliana or C. reinhardtii severely impaired PSII accumulation (Cecchin, Jeong, et al, 2021;Schneider et al, 2014;Spaniol et al, 2022;Wakao et al, 2021). Interestingly, no differential expression for proteins involved in carbon fixation was found in HL vs. LL C. vulgaris cells, but a protein predicted as chloroplast ferredoxin-thioredoxin reductase (g1978.t1) was downregulated in HL.…”