Immune outposts inside tumors predict post-surgery outcomes

The immune system establishes “forward operating bases”, or lymph node-like structures, inside the tumors of some patients with kidney and other urologic Read more

Hedgehog pathway outside cilia (with CBD bonus)

The Hedgehog pathway has roles in both specifying what embryonic cells will become and in guiding growing neural Read more

Tracking how steroid hormone receptor proteins evolved

When thinking about the evolution of female and male, consider that the first steroid receptor proteins, which emerged about 550 million years ago, were responsive to estrogen. The ancestor of other steroid hormone receptors, responsive to hormones such as testosterone, progesterone and cortisol, emerged many millions of years later. Biochemist Eric Ortlund and colleagues have a new paper in Structure that reconstructs how interactions of steroid receptor proteins evolved over time. This is a complex Read more

dendritic spines

Seeing the nuts and bolts of neurons

Cool photo alert! James Zheng’s lab at Emory is uncommonly good at making photos and movies showing how neurons remodel themselves. They recently published a paper in Journal of Cell Biology showing how dendritic spines, which are small protrusions on neurons, contain concentrated pools of G-actin.

Actin, the main component of cells’ internal skeletons, is a small sturdy protein that can form long strings or filaments. It comes in two forms: F-actin (filamentous) or G-actin (globular). It is not an exaggeration to call F- and G-actin neurons’ “nuts and bolts.”

Think of actin monomers like Lego bricks. They can lock together in regular structures, or they can slosh around in a jumble. If the cell wants to build something, it needs to grab some of that slosh (G-actin) and turn them into filaments. Remodeling involves breaking down the filaments.

At Lab Land’s request, postdoc and lead author Wenliang Lei picked out his favorite photos of neurons, which show F-actin in red and G-actin in green. Zheng’s lab has developed probes that specifically label the F- and G- forms. Where both forms are present, such as in the dendritic spines, an orange or yellow color appears.

Why care about actin and dendritic spines?

*The Journal of Cell Biology paper identified the protein profilin as stabilizing neurons’ pool of G-actin. Profilin is mutated in some cases of ALS (amyotrophic lateral sclerosis), although exactly how the mutations affect actin dynamics is now under investigation.

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Posted on by Quinn Eastman in Neuro Leave a comment