Posted by: Dan | November 13, 2006

Cell Biology News

Cell Structure:

  • From the archives, Bora provides a comprehensive review of the structure of cells for an Intro to Biology class. Plenty of good pictures from the textbooks, and simple overviews, for the non-expert.

Permission To Create Chimeras For Stem Cell Research:

  • At Newcastle University, UK, and Kings College, London, UK, the scientists have found a route for creating stem cell lines. They want to get animals’ eggs and place human nuclei inside them, as this research would help for a better understanding of how to cure diseases such as Parkinson’s Diseasea and strokes. This route would free scientists from using donated human eggs.

How Doa10p gets into the nucleus, or another freaky experiment done in yeast:

  • I heard about this paper (Deng and Hochstrasser. Nature (06) 443:827-831) and took a look at it over the weekend. Wow! There are lots of goodies in there. And it showcases how manipulable yeast are. (As you can tell I am really jealous of researchers who use yeast as a model system.) The premise of the paper is not bad either. There had been some rumours that proteins could get degraded within the nucleus through the ubiquitin/proteosome pathway. Now to some this idea was heretical but this new paper gives some mechanistic info into how this process occurs.

Activating RNAs (RNAa) – another twist:

  • A paper published online in PNAS described a possible new form of regulation of gene expression by small RNAs. The authors found that small dsRNAs can also serve as transcriptional activators. They showed that the mechanism for gene expression activation also prefers dsRNAs of ~21 nt in size and requires the Argonaute 2 protein.


  • Protein phosphorylation is a hot topic in signal transduction research. Kinases can add phosphate groups to serines, threonines & tyrosines (and very rarely histidines), and phosphatases can take them off. These phosphorylations can shift the shape of the protein directly, or create (or destroy) binding sites for other proteins. Such bindings can in turn cause the assembly/disassembly of protein complexes, trigger the transport of a protein to another part of the cell, or lead to the protein being destroyed (or prevent such) by the proteasome. This is hardly a comprehensive list of what can happen.

A series on the published sea urchin genome:

More from ScienceDaily and EurekAlert below the fold:

One signal elicits thousands of answers:

  • Cell signaling mechanisms often transmit information via protein modifications, most importantly the reversible attachment of phosphate, the so-called protein phosphorylation. Researchers at the Max Planck Institute of Biochemistry in Martinsried have now developed a technology to identify and quantify the specific sites in proteins that get phosphorylated in answer to certain stimuli in living cells. Under the lead of Matthias Mann, the scientists found 6,600 phosphorylation sites – 90 percent of which were unknown – in 2,244 proteins and observed their temporal dynamics. All these phosphorylation sites are now listed in the newly created Phosida database to make them available for efficient use by scientists working in different areas, among them tumour researchers: Defects in cellular signaling often occur in many types of cancer (Cell, November 2, 2006).

Growth Factor Signals Influence Balance Between Normal Growth And Cancerous Growth:

  • For many biological processes, the Goldilocks Principle rules. You don’t want too much, or too little, of something, you want it just right. So it is with the body’s delicate concentration of growth factors. Too much of a signaling protein called insulin-like growth factor-I (IGF-I) may fan the flames of cancer, while too little of the protein may cause short stature, dementia and osteoporosis, among other problems. New research from The Children’s Hospital of Philadelphia and the University of Pennsylvania School of Medicine deepens the understanding of how the growth hormone/IGF system is affected by another important actor: p53, the tumor suppressor gene that puts the brakes on cancer. The interplay of the two signaling pathways reinforces questions about the long-term risks of prescribing growth hormone and IGF-I to patients, at the same time that it may suggest a future new avenue for cancer therapy.

Two Nerve Cells In Direct Contact:

  • For the first time, scientists at the Max Planck Institute for Neurobiology in Martinsried near Munich have been able to show how two nerve cells communicate with each other from different hemispheres in the visual centre. This astoundingly simple circuit diagram could at a later date provide a model for algorithms to be deployed in technical systems (Nature Neuroscience, October 10, 2006)


  1. PZ Myers has a post linking to some of his students’ writings on Devo that are quite nice too.


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