Are Zinc-Finger Domains of Protein Kinase C Dynamic Structures That Unfold by Lipid or Redox Activation?

Protein kinase C (PKC) is activated by lipid second messengers or redox action, raising the question whether these activation modes involve the same or alternate mechanisms. Here we show that both lipid activators and oxidation target the zinc-finger domains of PKC, suggesting a unifying activation mechanism. We found that lipid agonist-binding or redox action leads to zinc release and disassembly of zinc fingers, thus triggering large-scale unfolding that underlies conversion to the active enzyme. These results suggest that PKC zinc fingers, originally considered purely structural devices, are in fact redox-sensitive flexible hinges, whose conformation is controlled both by redox conditions and lipid agonists. Antioxid. Redox Signal. 14, 757-766.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90473/1/ars-2E2010-2E3773.pd

Open Sequence Initiative: a part submission standard to complement modern DNA assembly techniques

The discipline of synthetic biology emphasizes the application of engineering principles such as standardization, abstraction, modularity, and rational design to complex biological systems. The archetypical example of such standardization is BioBrick RFC[10], introduced in 2003 by Tom Knight at MIT. BioBricks are stored on a standard plasmid, pSB1C3, which contains prefix and suffix sequences flanking the DNA sequence specifying a biological part. The prefix and suffix sequences contain two pairs of 6 base-pair (bp) restriction enzyme sites (EcoRI+XbaI and SpeI+PstI), which can be used for both part assembly and quality control. BioBricks are intended to be well- characterized biological parts, such as genes or promoters, that function in a predictable fashion and can be readily combined to make complex systems. The rules of the RFC[10] BioBrick assembly method require that none of the restriction sites used in the prefix and suffix be present in the parts themselves. This requirement can be an onerous imposition for iGEM teams developing large, novel parts, such as genes or entire operons that are obtained by amplifying DNA sequences from environmental samples or microorganisms. While iGEM teams may use methods such as site-directed mutagenesis to remove illegal restriction sites from a part's sequence, it is certainly possible that this mutation will alter the functionality of the part – a very undesirable outcome. In addition, the mutagenesis of illegal restriction sites is an unnecessary burden on teams, given the limited time and resources available to teams during each year’s iGEM competition. Efforts spent mutagenizing sites would be better spent characterizing and improving parts. This RFC proposes an alternative submission standard to eliminate these problems

Tetraspanin CD53 promotes lymphocyte recirculation by stablising L-selectin surface expression

Tetraspanins regulate key processes in immune cells; however, the function of the leukocyterestricted tetraspanin, CD53 has remained unknown. Here we show that CD53 is essential for lymphocyte recirculation. Lymph nodes of Cd53-/- mice were smaller than wild-type mice due to a marked reduction in B cells and a 50% decrease in T cells. This reduced cellularity reflected an inability of Cd53-/- B and T cells to efficiently home to lymph nodes, due to the near absence of L-selectin from Cd53-/- B cells and reduced stability of L-selectin on Cd53-/- T cells. Further analyses, including on human lymphocytes, showed that CD53 inhibits L-selectin shedding via both ADAM17-dependent and -independent mechanisms. The disruption in lymphocyte recirculation in Cd53-/- mice led to impaired immune responses dependent on antigen delivery to lymph nodes. Together these findings demonstrate a previously unrecognized essential role for CD53 in lymphocyte trafficking and immune responses

The Role of I Region Gene Products in Macrophage - T Lymphocyte Interaction

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73965/1/j.1600-065X.1978.tb00400.x.pd