Golgi-to-plastid trafficking of proteins through secretory pathway: Insights into vesicle-mediated import toward the plastids

Abstract

The diversity of protein targeting pathways to plastids and their regulation in response to developmental and metabolic status is a key issue in the regulation of cellular function in plants. The general import pathways that target proteins into and across the plastid envelope with changes in gene expression are critical for plant development by regulating the response to physiological and metabolic changes within the cell. Glycoprotein targeting to complex plastids involves routing through the secretory pathway, among others. However, the mechanisms of trafficking via this system remain poorly understood. The present article discusses our results in site-specific N-glycosylation of nucleotide pyrophosphatase/phosphodiesterases (NPPs) glycoproteins and highlights protein delivery in Golgi/plastid pathway via the secretory pathway. Furthermore, we outline the hypotheses that explain the mechanism for importing vesicles trafficking with nucleus-encoded proteins into plastids.

Protein import into chloroplasts and its regulation by the ubiquitin-proteasome system

“…It has recently emerged that other β-barrel proteins may insert with the aid of a TP [43], and those that do not may be targeted to the chloroplast by their penultimate β-barrel strand [44] via components of the TOC apparatus [43]. Lastly, there exist at least two non-canonical pathways of chloroplast protein targeting, which deliver internal proteins lacking an N-terminal signal in TOC-independent fashion [45], or involve passage through the endomembrane system [46].…”

Photosynthesis in a Changing Global Climate: Scaling Up and Scaling Down in Crops

“…Photosynthesis is mediated by the coordinated action of ca. 3000 nuclear-encoded preproteins synthesized in the cytosol and imported into organelles through special machineries (Nakai, 2015;Baslam et al, 2016) in envelope membranes. About 2400 of these proteins are found in the chloroplast (Friso et al, 2004), while only ca.…”

Proteomics Analysis Reveals Non-Controlled Activation of Photosynthesis and Protein Synthesis in a Rice npp1 Mutant under High Temperature and Elevated CO2 Conditions

“…The NPP genes are located on chromosomes 3 ( NPP3 ), 8 ( NPP1 ), 9 ( NPP6 ), and 12 ( NPP2 , 4 , 5 ) in the rice genome. Although NPP3 was exclusively localized in the endomembrane system [ 15 ], NPP1 , 2, and 6 exhibited a dual localization in both the plastid and endomembrane systems [ 13 , 16 , 17 ], as has been found for other plastidial glycoproteins [ 18 , 19 , 20 , 21 , 22 ]. Whereas NPP1 and NPP6 recognized nucleotide sugars, NPP2 did not recognize these compounds as substrates but preferentially hydrolyzed uridine diphosphate (UDP), ADP, and adenosine 5′-phosphosulfate (APS).…”