The Arabidopsis Protein Disulfide Isomerase Subfamily M Isoform, PDI9, Localizes to the Endoplasmic Reticulum and Influences Pollen Viability and Proper Formation of the Pollen Exine During Heat Stress.

Plants adapt to heat thermotolerance pathways in which the activation of protein folding chaperones is essential. In eukaryotes, protein disulfide isomerases (PDIs) facilitate the folding of nascent and misfolded proteins in the secretory pathway by catalyzing the formation and isomerization of disulfide bonds and serving as molecular chaperones. In Arabidopsis, several members of the PDI family are upregulated in response to chemical inducers of the unfolded protein response (UPR), including both members of the non-classical PDI-M subfamily, PDI9 and PDI10.

A Non-Classical Member of the Protein Disulfide Isomerase Family, PDI7 of Arabidopsis thaliana, Localizes to the cis-Golgi and Endoplasmic Reticulum Membranes.

Members of the protein disulfide isomerase (PDI)-C subfamily are chimeric proteins containing the thioredoxin (Trx) domain of PDIs, and the conserved N- and C-terminal Pfam domains of Erv41p/Erv46p-type cargo receptors. They are unique to plants and chromalveolates. The Arabidopsis genome encodes three PDI-C isoforms: PDI7, PDI12 and PDI13.

Arabidopsis protein disulfide isomerase-8 is a type I endoplasmic reticulum transmembrane protein with thiol-disulfide oxidase activity.

Background: In eukaryotes, classical protein disulfide isomerases (PDIs) facilitate the oxidative folding of nascent secretory proteins in the endoplasmic reticulum by catalyzing the formation, breakage, and rearrangement of disulfide bonds. Terrestrial plants encode six structurally distinct subfamilies of PDIs. The novel PDI-B subfamily is unique to terrestrial plants, and in Arabidopsis is represented by a single member, PDI8.

Phylogenetic characterization and promoter expression analysis of a novel hybrid protein disulfide isomerase/cargo receptor subfamily unique to plants and chromalveolates.

Protein disulfide isomerases (PDIs) play critical roles in protein folding by catalyzing the formation and rearrangement of disulfide bonds in nascent secretory proteins. There are six distinct PDI subfamilies in terrestrial plants. A unique feature of PDI-C subfamily members is their homology to the yeast retrograde (Golgi-to-endoplasmic reticulum) cargo receptor proteins, Erv41p and Erv46p.

Dual protein trafficking to secretory and non-secretory cell compartments: clear or double vision?

Approximately 18% of Arabidopsis thaliana proteins encode a signal peptide for translocation to the endoplasmic reticulum (ER), the gateway of the eukaryotic secretory pathway. However, it was recently discovered that some ER proteins can undergo both co-translational import into the ER/secretory pathway and trafficking to compartments outside of the secretory pathway. This phenomenon is observed among members of the protein disulfide isomerase (PDI) family, which are traditionally regarded as ER enzymes involved in protein folding.

Variation in the Subcellular Localization and Protein Folding Activity among Arabidopsis thaliana Homologs of Protein Disulfide Isomerase.

Protein disulfide isomerases (PDIs) catalyze the formation, breakage, and rearrangement of disulfide bonds to properly fold nascent polypeptides within the endoplasmic reticulum (ER). Classical animal and yeast PDIs possess two catalytic thioredoxin-like domains (a, a') and two non-catalytic domains (b, b'), in the order a-b-b'-a'. The model plant, Arabidopsis thaliana, encodes 12 PDI-like proteins, six of which possess the classical PDI domain arrangement (AtPDI1 through AtPDI6).

Protein disulfide isomerase-2 of Arabidopsis mediates protein folding and localizes to both the secretory pathway and nucleus, where it interacts with maternal effect embryo arrest factor.

Protein disulfide isomerase (PDI) is a thiodisulfide oxidoreductase that catalyzes the formation, reduction and rearrangement of disulfide bonds in proteins of eukaryotes. The classical PDI has a signal peptide, two CXXC-containing thioredoxin catalytic sites (a,a'), two noncatalytic thioredoxin fold domains (b,b'), an acidic domain (c) and a C-terminal endoplasmic reticulum (ER) retention signal. Although PDI resides in the ER where it mediates the folding of nascent polypeptides of the secretory pathway, we recently showed that PDI5 of Arabidopsis thaliana chaperones and inhibits cysteine proteases during trafficking to vacuoles prior to programmed cell death of the endothelium in developing seeds.

The cyclic nucleotide gated cation channel AtCNGC10 traffics from the ER via Golgi vesicles to the plasma membrane of Arabidopsis root and leaf cells.

Background: The cyclic nucleotide-gated ion channels (CNGCs) maintain cation homeostasis essential for a wide range of physiological processes in plant cells. However, the precise subcellular locations and trafficking of these membrane proteins are poorly understood. This is further complicated by a general deficiency of information about targeting pathways of membrane proteins in plants.

WVD2 is a novel microtubule-associated protein in Arabidopsis thaliana.

Arabidopsis WAVE-DAMPENED 2 (WVD2) was identified by forward genetics as an activation-tagged allele that causes plant and organ stockiness and inversion of helical root growth handedness on agar surfaces. Plants with high constitutive expression of WVD2 or other members of the WVD2-LIKE (WDL) gene family have stems and roots that are short and thick, have reduced anisotropic cell elongation, are suppressed in a root-waving phenotype, and have inverted handedness of twisting in hypocotyls and roots compared with wild-type. The wvd2-1 mutant shows aberrantly organized cortical microtubules in peripheral root cap cells as well as reduced branching of trichomes, unicellular leaf structures whose development is regulated by microtubule stability.

Loss-of-function mutations of ROOT HAIR DEFECTIVE3 suppress root waving, skewing, and epidermal cell file rotation in Arabidopsis.

Wild-type Arabidopsis (Arabidopsis thaliana L. Heynh.) roots growing on a tilted surface of impenetrable hard-agar media adopt a wave-like pattern and tend to skew to the right of the gravity vector (when viewed from the back of the plate through the medium).

WVD2 and WDL1 modulate helical organ growth and anisotropic cell expansion in Arabidopsis.

Wild-type Arabidopsis roots develop a wavy pattern of growth on tilted agar surfaces. For many Arabidopsis ecotypes, roots also grow askew on such surfaces, typically slanting to the right of the gravity vector. We identified a mutant, wvd2-1, that displays suppressed root waving and leftward root slanting under these conditions.