High impact information on ATELP1

• Further, we found that AtELP interacts in a similar manner with the NTPP of the endogenous vacuolar protein AtALEU (Arabidopsis thaliana Aleu), a protein highly homologous to barley aleurain [1].
• AtELP extracted from microsomes was found to interact with the NTPPs of barley aleurain and Spo, but not with the CTPPs of BL or tobacco chitinase, in a pH-dependent and sequence-specific manner [1].
• In addition, EM studies revealed the colocalization of AtELP with NTPP-Spo at the Golgi apparatus, but not with BL-CTPP in roots of transgenic Arabidopsis plants [1].
• Protein pull-down and coimmunoprecipitation experiments reveal that Arabidopsis EPSIN1 interacts with clathrin, VTI11, gamma-adaptin-related protein (gamma-ADR), and vacuolar sorting receptor1 (VSR1) [2].
• Anterograde transport proceeds normally from the endoplasmic reticulum to the Golgi and the PVC, although export from the PVC appears to be compromised, affecting both anterograde membrane flow to the vacuole and the recycling route of BP80 to the Golgi [3].

Biological context of ATELP1

• AtELP may therefore serve as a marker for compartments involved in intracellular protein trafficking in the plant cell [4].
• A cDNA clone, AtELP1 (Arabidopsis thaliana EGF receptor-like protein) was isolated from an Arabidopsis cDNA library with an oligonucleotide probe corresponding to a highly conserved region of animal beta-integrins [5].
• The genome of Arabidopsis (Arabidopsis thaliana) contains seven VSR proteins, but little is known about their individual subcellular localization and function [6].

Anatomical context of ATELP1

• Based on these data, we propose that EPSIN1 plays an important role in the vacuolar trafficking of soluble proteins at the trans-Golgi network via its interaction with gamma-ADR, VTI11, VSR1, and clathrin [2].
• The BP-80 protein is present in dilated ends of Golgi cisternae and in "prevacuoles," which are small vacuoles separate from but capable of fusing with lytic vacuoles [7].
• BP-80 is a type I integral membrane protein abundant in pea (Pisum sativum) clathrin-coated vesicles (CCVs) that binds with high affinity to vacuole-targeting determinants containing asparagine-proline-isoleucine-arginine [7].
• More than 90% of the BP-80-marked organelles are separate from Golgi organelles; thus, BP-80 and its homologs are predominantly concentrated on the lytic PVCs [8].
• In the present work, using two specific independent sets of anti-peptide antibodies, we show that AtELP1 is mainly located in the plasma membrane, supporting another function for this protein [5].

Associations of ATELP1 with chemical compounds

• Sucrose-density gradient fractionation demonstrated that AtVPS45p co-fractionates with AtELP, a potential vacuolar protein sorting receptor, implying that they may reside on the same membrane populations [9].
• The AtBP80b protein (560 amino acids) was crystallized by the hanging-drop method with a PEG 400-based precipitant [10].

Co-localisations of ATELP1

• Using subcellular fractionation and immunoelectron microscopy, we show that AtVTI1a colocalizes with the putative vacuolar cargo receptor AtELP on the trans-Golgi network and the PVC [11].
• Further, consistent with a role in trafficking of vacuolar cargo, we have found that AtELP partially colocalizes with AtPEP12p on a prevacuolar compartment [12].

Other interactions of ATELP1

• AtVPS45 is a member of this family from Arabidopsis thaliana that we now demonstrate to be present on the trans-Golgi network (TGN), where it colocalizes with the vacuolar cargo receptor AtELP [13].
• Two likely members of this trafficking machinery have been characterized from Arabidopsis thaliana: AtPEP12p, a t-SNARE that resides on a what we now call a prevacuolar compartment, and AtELP, a protein that shares many common features with mammalian and yeast transmembrane cargo receptors [12].

Analytical, diagnostic and therapeutic context of ATELP1

• We have thus demonstrated in plant cells that VSR proteins are predominantly present in the lytic PVCs and have provided additional markers for defining plant PVCs using confocal immunofluorescence [8].
• Northern blot analysis of AtELP1, 2b and 3 was performed on mRNA extracted from cells cultured in normal and stressed conditions, and from several organs and plants submitted to biotic or abiotic stresses [5].
• Preliminary data suggesting that retromer interacts with the cytosolic domain of a VSR were obtained by immunoprecipitation experiments performed on detergent-solubilized microsomes with Vps35 antibodies [14].

References