Regulation of lamp2a levels in the lysosomal membrane

The selective degradation of cytosolic proteins in lysosomes by chaperone-mediated autophagy depends, at least in part, on the levels of a substrate receptor at the lysosomal membrane. We have previously identified this receptor as the lysosome-associated membrane protein type 2a (lamp2a) and showed that levels of lamp2a at the lysosomal membrane directly correlate with the activity of the proteolytic pathway. Here we show that levels of lamp2a at the lysosomal membrane are mainly controlled by changes in its half-life and its distribution between the lysosomal membrane and the matrix. The lysosomal degradation of lamp2a requires the combined action of at least two different proteolytic activities at the lysosomal membrane. Lamp2a is released from the membrane by the action of these proteases, and then the truncated lamp2a is rapidly degraded within the lysosomal matrix. Membrane degradation of lamp2a is a regulated process that is inhibited in the presence of substrates for chaperone-mediated autophagy and under conditions that activate that type of autophagy. Uptake of substrate proteins also results in transport of some intact lamp2a from the lysosomal membrane into the matrix. This fraction of lamp2a can be reinserted back into the lysosomal membrane. The traffic of lamp2a through the lysosomal matrix is not mediated by vesicles, and lamp2a reinsertion requires the lysosomal membrane potential and protein components of the lysosomal membrane. The distribution of lamp2a between the lysosomal membrane and matrix is a dynamic process that contributes to the regulation of lysosomal membrane levels of lamp2a and consequently to the activity of the chaperone-mediated autophagic pathway

Multidataset Incremental Training for Optic Disc Segmentation

When convolutional neural networks are applied to image segmentation results depend greatly on the data sets used to train the networks. Cloud providers support multi GPU and TPU virtual machines making the idea of cloud-based segmentation as service attractive. In this paper we study the problem of building a segmentation service, where images would come from different acquisition instruments, by training a generalized U-Net with images from a single or several datasets. We also study the possibility of training with a single instrument and perform quick retrains when more data is available. As our example we perform segmentation of Optic Disc in fundus images which is useful for glau coma diagnosis. We use two publicly available data sets (RIM-One V3, DRISHTI) for individual, mixed or incremental training. We show that multidataset or incremental training can produce results that are simi lar to those published by researchers who use the same dataset for both training and validation

Methodology for registration of distended recutms in pelvic CT studies

Purpose: Accurate delineation of the rectum is of high importance in off-line adaptive radiation therapy since it is a major dose-limiting organ in prostate cancer radiotherapy. The intensity-based deformable image registration (DIR) methods cannot create a correct spatial transformation if there is no correspondence between the template and the target images. The variation of rectal filling, gas, or feces, creates a noncorrespondence in image intensities that becomes a great obstacle for intensity-based DIR. Methods: In this study the authors have designed and implemented a semiautomatic method to create a rectum mask in pelvic computed tomography (CT) images. The method, that includes a DIR based on the demons algorithm, has been tested in 13 prostate cancer cases, each comprising of two CT scans, for a total of 26 CT scans. Results: The use of the manual segmentation in the planning image and the proposed rectum mask method (RMM) method in the daily image leads to an improvement in the DIR performance in pelvic CT images, obtaining a mean value of overlap volume index = 0.89, close to the values obtained using the manual segmentations in both images. Conclusions: The application of the RMM method in the daily image and the manual segmentations in the planning image during prostate cancer treatments increases the performance of the registration in presence of rectal fillings, obtaining very good agreement with a physician's manual contours

Hsp70 in mitochondrial biogenesis

The family of hsp70 (70 kilodalton heat shock protein) molecular chaperones plays an essential and diverse role in cellular physiology, Hsp70 proteins appear to elicit their effects by interacting with polypeptides that present domains which exhibit non-native conformations at distinct stages during their life in the cell. In this paper we review work pertaining to the functions of hsp70 proteins in chaperoning mitochondrial protein biogenesis. Hsp70 proteins function in protein synthesis, protein translocation across mitochondrial membranes, protein folding and finally the delivery of misfolded proteins to proteolytic enzymes in the mitochondrial matrix

WebCSD: the online portal to the Cambridge Structural Database

The new web-based application WebCSD is introduced, which provides a range of facilities for searching the Cambridge Structural Database within a standard web browser. Search options within WebCSD include two-dimensional substructure, molecular similarity, text/numeric and reduced cell searching

Extending the rapeseed gene pool with resynthesized Brassica napus II: Heterosis

Hybrid breeding relies on the combination of parents from two differing heterotic groups. However, the genetic diversity in adapted oilseed rape breeding material is rather limited. Therefore, the use of resynthesized Brassica napus as a distant gene pool was investigated. Hybrids were derived from crosses between 44 resynthesized lines with a diverse genetic background and two male sterile winter oilseed rape tester lines. The hybrids were evaluated together with their parents and check cultivars in 2 years and five locations in Germany. Yield, plant height, seed oil, and protein content were monitored, and genetic distances were estimated with molecular markers (127 polymorphic RFLP fragments). Resynthesized lines varied in yield between 40.9 dt/ha and 21.5 dt/ha, or between 85.1 and 44.6% of check cultivar yields. Relative to check cultivars, hybrids varied from 91.6 to 116.6% in yield and from 94.5 to 103.3% in seed oil content. Mid-parent heterosis varied from −3.5 to 47.2% for yield. The genetic distance of parental lines was not significantly correlated with heterosis or hybrid yield. Although resynthesized lines do not meet the elite rapeseed standards, they are a valuable source for hybrid breeding due to their large distance from present breeding material and their high heterosis when combined with European winter oilseed rape

Mapping and identification of candidate loci responsible for Peromyscus hybrid overgrowth

Crosses between two recently diverged rodent species of the genus Peromyscus result in dramatic parent-of-origin effects on growth and development. P. maniculatus females crossed with P. polionotus males yield growth-retarded conceptuses, whereas the reciprocal cross results in overgrowth and lethality. These hybrid effects are particularly pronounced in the placenta. We previously detected linkage to two regions of the genome involved in the overgrowth effects. One locus, termed Peal, is a paternally expressed autosomal locus mapping to a domain whose house mouse equivalent contains several clusters of imprinted genes. The other locus, termed Mexl, maps to a gene-poor region of the X chromosome. Here we use an advanced intercross line to verify and narrow the regions of linkage and identify candidate genes for Mexl and Peal. While we have previously shown that Mexl affects both pre-and postnatal growth, we show here that Peal affects only prenatal growth. Utilizing criteria such as mutant phenotypes and allelic expression, we identify the loci encoding the homeobox protein Esx1 and the zinc-finger protein Pw1/Peg3 as candidates. Both loci exhibit expression changes in the hybrids