| 1. |
- Chenouard, Nicolas, et al.
(författare)
-
Objective comparison of particle tracking methods
- 2014
-
Ingår i: Nature Methods. - : Springer Science and Business Media LLC. - 1548-7091 .- 1548-7105. ; 11:3, s. 281-U247
-
Tidskriftsartikel (refereegranskat)abstract
- Particle tracking is of key importance for quantitative analysis of intracellular dynamic processes from time-lapse microscopy image data. Because manually detecting and following large numbers of individual particles is not feasible, automated computational methods have been developed for these tasks by many groups. Aiming to perform an objective comparison of methods, we gathered the community and organized an open competition in which participating teams applied their own methods independently to a commonly defined data set including diverse scenarios. Performance was assessed using commonly defined measures. Although no single method performed best across all scenarios, the results revealed clear differences between the various approaches, leading to notable practical conclusions for users and developers.
|
|
| 2. |
- Chivasso, Clara, et al.
(författare)
-
Unraveling human aqp5-pip molecular interaction and effect on aqp5 salivary glands localization in ss patients
- 2021
-
Ingår i: Cells. - : MDPI AG. - 2073-4409. ; 10:8
-
Tidskriftsartikel (refereegranskat)abstract
- Saliva secretion requires effective translocation of aquaporin 5 (AQP5) water channel to the salivary glands (SGs) acinar apical membrane. Patients with Sjögren’s syndrome (SS) display abnormal AQP5 localization within acinar cells from SGs that correlate with sicca manifestation and glands hypofunction. Several proteins such as Prolactin-inducible protein (PIP) may regulate AQP5 trafficking as observed in lacrimal glands from mice. However, the role of the AQP5-PIP complex remains poorly understood. In the present study, we show that PIP interacts with AQP5 in vitro and in mice as well as in human SGs and that PIP misexpression correlates with an altered AQP5 distribution at the acinar apical membrane in PIP knockout mice and SS hMSG. Furthermore, our data show that the protein-protein interaction involves the AQP5 C-terminus and the N-terminal of PIP (one molecule of PIP per AQP5 tetramer). In conclusion, our findings highlight for the first time the role of PIP as a protein controlling AQP5 localization in human salivary glands but extend beyond due to the PIP-AQP5 interaction described in lung and breast cancers.
|
|
| 3. |
- Gustavsson, Sofia, et al.
(författare)
-
A novel plant major intrinsic protein in Physcomitrella patens most similar to bacterial glycerol channels
- 2005
-
Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 1532-2548 .- 0032-0889. ; 139:1, s. 287-295
-
Tidskriftsartikel (refereegranskat)abstract
- A gene encoding a novel fifth type of major intrinsic protein (MIP) in plants has been identified in the moss Physcomitrella patens. Phylogenetic analyses show that this protein, GlpF-like intrinsic protein (GIP1;1), is closely related to a subclass of glycerol transporters in bacteria that in addition to glycerol are highly permeable to water. A likely explanation of the occurrence of this bacterial-like MIP in P. patens is horizontal gene transfer. The expressed P. patens GIP1;1 gene contains five introns and encodes a unique C-loop extension of approximately 110 amino acid residues that has no obvious similarity with any other known protein. Based on alignments and structural comparisons with other MIPs, GIP1;1 is suggested to have retained the permeability for glycerol but not for water. Studies on heterologously expressed GIP1;1 in Xenopus laevis oocytes confirm the predicted substrate specificity. Interestingly, proteins of one of the plant-specific subgroups of MIPs, the NOD26-like intrinsic proteins, are also facilitating the transport of glycerol and have previously been suggested to have evolved from a horizontally transferred bacterial gene. Further studies on localization and searches for GIP1;1 homologs in other plants will clarify the function and significance of this new plant MIP.
|
|
| 4. |
- Kirscht, Andreas, et al.
(författare)
-
Crystal Structure of an Ammonia-Permeable Aquaporin
- 2016
-
Ingår i: PLoS Biology. - : Public Library of Science (PLoS). - 1545-7885. ; 14:3
-
Tidskriftsartikel (refereegranskat)abstract
- Aquaporins of the TIP subfamily (Tonoplast Intrinsic Proteins) have been suggested to facilitate permeation of water and ammonia across the vacuolar membrane of plants, allowing the vacuole to efficiently sequester ammonium ions and counteract cytosolic fluctuations of ammonia. Here, we report the structure determined at 1.18 Å resolution from twinned crystals of Arabidopsis thaliana aquaporin AtTIP2;1 and confirm water and ammonia permeability of the purified protein reconstituted in proteoliposomes as further substantiated by molecular dynamics simulations. The structure of AtTIP2;1 reveals an extended selectivity filter with the conserved arginine of the filter adopting a unique unpredicted position. The relatively wide pore and the polar nature of the selectivity filter clarify the ammonia permeability. By mutational studies, we show that the identified determinants in the extended selectivity filter region are sufficient to convert a strictly water-specific human aquaporin into an AtTIP2;1-like ammonia channel. A flexible histidine and a novel water-filled side pore are speculated to deprotonate ammonium ions, thereby possibly increasing permeation of ammonia. The molecular understanding of how aquaporins facilitate ammonia flux across membranes could potentially be used to modulate ammonia losses over the plasma membrane to the atmosphere, e.g., during photorespiration, and thereby to modify the nitrogen use efficiency of plants.
|
|
