Endocytosis and Intracellular Trafficking of Human Natural Killer Cell Receptors

Natural killer (NK) cells play a vital role in the defense against viral infections and tumor development. NK cell function is primarily regulated by the sum of signals from a broad array of activation and inhibitory receptors. Key to generating the input level of either activating or inhibitory signals is the maintenance of receptor expression levels on the cell surface. Although the mechanisms of endocytosis and trafficking for some cell surface receptors, such as transferrin receptor and certain immune receptors, are very well known, that is not the situation for receptors expressed by NK cells. Recent studies have uncovered that endocytosis and trafficking routes characteristic for specific activation and inhibitory receptors can regulate the functional responses of NK cells. In this review, we summarize the current knowledge of receptor endocytosis and trafficking, and integrate this with our current understanding of NK cell receptor trafficking.     

An ICEBs1-like element may be associated with the extreme radiation and desiccation resistance of Bacillus pumilus SAFR-032 spores

Comparisons of the genomes of Bacillus pumilus SAFR-032 and the closely related type strain, B. pumilus ATCC7061^T, exposed an extended region of non-homologous genes. A detailed examination of this region revealed the presence of an ICEBs1-like integrative conjugative element in SAFR-032. A similar element was subsequently located elsewhere in the ATCC7061^T genome. A detailed comparison of these elements and the ICEBs1 of B. subtilis revealed extremely rapid flux in gene content, genome organization and sequence similarity. It is not clear if the B. pumilus elements as they are currently structured are functional. However, it is clear that the past involvement of these elements has brought multiple genes of unknown function to the SAFR-032 genome and these genes may be responsible for the rapid evolution that led to the extreme radiation and desiccation resistance of this organism’s spores.     

Optical Channel Drop Filter Design Based on PCRR and Micro Cavity Resonator

Optical channel drop filter (OCDF) plays a key role in optical communication networks for filtering the individual wavelength among the group of channels in wavelength division multiplexing systems. There are several channel drop filters with different design mechanisms available in the literature, but those structure dimensions are not compact enough for the photonic integrated applications. Hence, in this paper, a compact and efficient OCDF is developed in the triangular lattice PC structure based on diamond-shaped photonic crystal ring resonator (PCRR) mechanism combined with micro cavity resonator (MCR). The developed OCDF is analysed for different operating wavelengths by considering the different positions of MCR around the main PCRR. Based upon the position of the MCR around PCRR, the three dropping wavelengths such as 1540 nm, 1550 nm, and 1570 nm are observed at the output waveguides with 100% dropping efficiency. Then the structural and performance parameter comparison is done between the proposed and existing structures in terms of device dimension, dropping efficiency, and quality factor. It is depicted through the results that the quality factor and the device dimension are better than that of the existing structures for 1550-nm wavelength.