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Membrane identity and dynamic processes, that act at membrane sites, provide important cues for regulating transport, signal transduction and communication across membranes. There are still numerous open questions as to how membrane identity changes and the dynamic processes acting at the surface of membranes are regulated in diverse eukaryotes in particular plants and which roles are being played by protein interaction complexes composed of peripheral and integral membrane proteins. One class of peripheral membrane proteins conserved across eukaryotes comprises the SEC14-like phosphatidylinositol transfer proteins (SEC14L-PITPs). These proteins share a SEC14 domain that contributes to membrane identity and fulfills regulatory functions in membrane trafficking by its ability to sense, bind, transport and exchange lipophilic substances between membranes, such as phosphoinositides and diverse other lipophilic substances. SEC14L-PITPs can occur as single-domain SEC14-only proteins in all investigated organisms or with a modular domain structure as multi-domain proteins in animals and streptophytes (comprising charales and land plants). Here, we present an overview on the functional roles of SEC14L-PITPs, with a special focus on the multi-domain SEC14L-PITPs of the SEC14-nodulin and SEC14-GOLD group (PATELLINs, PATLs in plants). This indicates that SEC14L-PITPs play diverse roles from membrane trafficking to organism fitness in plants. We concentrate on the structure of SEC14L-PITPs, their ability to not only bind phospholipids but also other lipophilic ligands, and their ability to regulate complex cellular responses through interacting with proteins at membrane sites.

The sessile lifestyle of plants requires them to cope with stresses in situ. Plants overcome abiotic stresses by altering structure/morphology, and in some extreme conditions, by compressing the life cycle to survive the stresses in the form of seeds. Genetic and molecular studies have uncovered complex regulatory processes that coordinate stress adaptation and tolerance in plants, which are integrated at various levels. Investigating natural variation in stress responses has provided important insights into the evolutionary processes that shape the integrated regulation of adaptation and tolerance. This review primarily focuses on the current understanding of how transcriptional, post-transcriptional, post-translational, and epigenetic processes along with genetic variation orchestrate stress responses in plants. We also discuss the current and future development of computational tools to identify biologically meaningful factors from high dimensional, genome-scale data and construct the signaling networks consisting of these components.

Endosomal recycling of plasma-membrane proteins contributes significantly to the regulation of cellular transport and signaling processes. Members of the Arabidopsis (Arabidopsis thaliana) SORTING NEXIN (SNX) protein family were shown to mediate the endosomal retrieval of transporter proteins in response to external challenges. Our aim is to understand the possible ways through which external stimuli influence the activity of SNX1 in the root. Several proteins are known to contribute to the function of SNX1 through direct protein-protein interaction. We, therefore, compiled a list of all Arabidopsis proteins known to physically interact with SNX1 and employed available gene expression and proteomic data for a comprehensive analysis of the transcriptional and post-transcriptional regulation of this interactome. The genes encoding SNX1-interaction partners showed distinct expression patterns with some, like FAB1A, being uniformly-expressed, while others, like MC9 and BLOS1, were expressed in specific root zones and cell types. Under stress conditions known to induce SNX1-dependent responses, two genes encoding SNX1-interacting proteins, MC9 and NXH6, showed major gene-expression variations. We could also observe zone-specific transcriptional changes of SNX1 under iron deficiency, which are consistent with the described role of the SNX1 protein. This suggests that the composition of potential SNX1-containing protein complexes in roots is cell-specific and may be readjusted in response to external stimuli. On the level of post-transcriptional modifications, we observed stress-dependent changes in the phosphorylation status of SNX1, FAB1A and CLASP. Interestingly, the phosphorylation events affecting SNX1 interactors occur in a pattern which is largely complementary to transcriptional regulation. Our analysis shows that transcriptional and post-transcriptional regulation play distinct roles in SNX1-mediated endosomal recycling under external stress.