ABSTRACT
Since December 2019, Corona Virus Disease (COVID-19), a new emerging infection disease occurred in Wuhan, has spread in 27 countries and regions. The clusters of many cases were reported with the epidemic progresses. We collected currently available information for 377 COVID-19 clusters (1 719 cases), excluded the hospital clusters and Hubei cases, during the period from January 1, 2020 to February 20, 2020. There were 297 family clusters (79%), case median 4; 39 clusters of dining (10%), case median 5; 23 clusters of shopping malls or supermarkets (6%), case median 13; 12 clusters of work units (3%), case median 6, and 6 clusters of transportation. We selected 325 cases to estimate the incubation period and found its range is 1 to 20 days, median was 7 days, and mode was 4 days. The analysis of the epidemic situation in a department store in China indicates that there is a possibility of patients as the source of infection during the incubation period of the epidemic. From February 5, 2020 to February 21, 2020, 634 persons were infected in the Diamond Princess Liner. All persons are susceptible to SARS-CoV-2. The older, patients during the incubation period and the worse environment may be the cause of the cases rising. The progress of the two typical outbreaks clearly demonstrates the spread of the early cases in Wuhan. Whatever happens, screening and isolating close contacts remains essential except for clinical treatment during the epidemic. Especially for the healthy people in the epidemic area, isolation is the key.
ABSTRACT
In all six members of TRPV channel subfamily, there is an ankyrin repeat domain (ARD) in their intracellular N-termini. Ankyrin (ANK) repeat, a common motif with typically 33 residues in each repeat, is primarily involved in protein-protein interactions. Despite the sequence similarity among the ARDs of TRPV channels, the structure of TRPV3-ARD, however, remains unknown. Here, we report the crystal structure of TRPV3-ARD solved at 1.95 Å resolution, which reveals six-ankyrin repeats. While overall structure of TRPV3-ARD is similar to ARDs from other members of TRPV subfamily; it, however, features a noticeable finger 3 loop that bends over and is stabilized by a network of hydrogen bonds and hydrophobic packing, instead of being flexible as seen in known TRPV-ARD structures. Electrophysiological recordings demonstrated that mutating key residues R225, R226, Q255, and F249 of finger 3 loop altered the channel activities and pharmacology. Taken all together, our findings show that TRPV3-ARD with characteristic finger 3 loop likely plays an important role in channel function and pharmacology.
Subject(s)
Humans , Amino Acid Sequence , Ankyrin Repeat , Crystallography, X-Ray , HEK293 Cells , Models, Molecular , Molecular Sequence Data , Patch-Clamp Techniques , Protein Binding , Protein Conformation , Protein Structure, Tertiary , Sequence Homology, Amino Acid , TRPV Cation Channels , Chemistry , PhysiologyABSTRACT
Kindlin-2 belongs to a subfamily of FERM domain containing proteins, which plays key roles in activating integrin transmembrane receptors and mediating cell adhesion. Compared to conventional FERM domains, kindlin-2 FERM contains an inserted pleckstrin homology (PH) domain that specifically binds to phosphatidylinositol (3,4,5) trisphosphate (PIP3) and regulates the kindlin-2 function. We have determined the crystal structure of kindlin-2 PH domain at 1.9 Å resolution, which reveals a conserved PH domain fold with a highly charged and open binding pocket for PIP3 head group. Structural comparison with a previously reported solution structure of kindlin-2 PH domain bound to PIP3 head group reveals that upon PIP3 insertion, there is a significant conformational change of both the highly positively charged loop at the entry of the PIP3 binding pocket and the entire β barrel of the PH domain. We propose that such "induced-fit" type change is crucial for the tight binding of PIP3 to anchor kindlin-2 onto the membrane surface, thereby promoting its binding to integrins. Our results provide important structural insight into kindlin-2-mediated membrane anchoring and integrin activation.