Despite extensive investigation, the precise mechanism controlling the opening of the cytoplasmic proton uptake pathway in bacteriorhodopsin (bR) has remained a mystery. From an analysis of the X-ray structure of the D96G/F171C/F219L triple mutant of bR and 60 independent molecular dynamics simulations of bR photointermediates, we report that the deprotonation of D96, a key residue in proton tr...

Many immune system receptors signal through cytoplasmic tyrosine-based motifs (ITAMs), but how receptor ligation results in ITAM phosphorylation remains unknown. Live-cell imaging studies showed a close interaction of the CD3epsilon cytoplasmic domain of the T cell receptor (TCR) with the plasma membrane through fluorescence resonance energy transfer between a C-terminal fluorescent protein and...

IL-15 is critical for natural killer (NK)–cell development and function and for memory CD8 T-cell homeostasis. The IL-15 receptor consists of IL-15R , IL-2R , and the common cytokine receptor chain ( c). IL-15R is known to “trans-present” IL-15 to an IL-2R / c heterodimeric receptor on responding cells to initiate signaling. To investigate the importance of the IL-15R cytoplasmic domain, we gen...

The proteolipid protein gene products DM-20 and PLP are adhesive intrinsic membrane proteins that make up >/=50% of the protein in myelin and serve to stabilize compact myelin sheaths at the extracellular surfaces of apposed membrane lamellae. To identify which domains of DM-20 and PLP are positioned topologically in the extracellular space to participate in adhesion, we engineered N-glycosylat...

This review examines current understanding of mammalian mitochondria and mitochondrial DNA in the light of new reproductive technologies. Mitochondria are central to ageing, apoptosis, metabolism and many diseases. They are controlled by a dual genome system, with cooperation between endogenous mitochondrial genes and mitochondrial genes translocated to the nucleus over the course of evolution....

According to a widely accepted view, the structure of chromosomal deoxyribonucleic acid in the nucleus determines the enzymatic composition of the cytoplasm. An attractive proposition which would explain this genetic control of cytoplasmic enzymes is that deoxyribonucleic acid in some way determines the structure of nuclear ribonucleic acid, that the nuclear ribonucleic acid passes out into the...

17 Introduction 18 Ovarian stimulation 20 In vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) 23 Immature sperm conception 25 Egg donation and surrogacy 28 Oocyte maturation 28 Embryo culture 30 Assisted hatching 31 Cryopreservation 32 Preimplantation genetic diagnosis (PGD) 34 Cytoplasmic donation and mitochondrial DNA (mDNA) transfer 37 Fertility preservation 39 Conclusion 41

Exchange of information is critical for bacterial social behaviors. Now Dubey and Ben-Yehuda (2011) provide evidence for bacterial "nanotube" conduits that allow microbes to directly exchange cytoplasmic factors. Protein and DNA transfer between distantly related species raises the prospect of a new, widely distributed mechanism of bacterial communication.

A conserved response to stress involves endonucleolytic cleavage of cytoplasmic transfer RNAs (tRNAs) by ribonucleases that are normally secreted or sequestered. Ribonuclease activation or release is an intriguing new aspect of cellular stress responses, with a potential impact on translation, apoptosis, cancer, and disease progression.