Dancing Molecules: Rewiring Cooperative Communications within 14-3-3 ζ Docking Proteins

Allosteric engineering may play a key role in novel drug discovery. As allosteric interactions are often associated with disease states where protein active sites are rendered constitutively active. Due to their role in regulating signal transduction in cells, we attempted to rewire cooperative communications within the 14-3-3 ζ docking protein. To avoid disruption of evolutionarily tuned interaction networks, we attempted to do so by applying the “Fundamental Theory of the Evolution Force: FTEF”. Whereby, we reversed the motion vector of the 14-3-3 ζ C’ terminal tail. We were also able to modify low frequency vibrational modes across 14-3-3 ζ conformational ensembles. Notably, synthetic evolution by FTEF anticipated evolution of the 14-3-3 ζ docking protein. And accentuated nonrandom patterns of deformation waves resulting in a gain of function mutation characterized by increased protein flexibility. As well as allowed us to discover a genome encoded spatial arrangement of strain that promotes translation of vibrational motions through protein structural layers. We also discovered a 14-3-3 ζ evolution blueprint that predetermines evolutional fate of the docking protein. The aforementioned suggests that the evolutionary fate of cells may be encoded in the genome, thusly may be predetermined. SignificanceAllostery plays a key role in disease. Wherein, mutations redistribute conformational ensembles and render proteins constitutively active. 14-3-3 docking proteins are key signaling proteins involved in multiple signal pathways that effect cell proliferation, cell cycle and apoptosis. Saliently, the 14-3-3 ζ isoform is associated with neurodegenerative disease, cancer and glaucoma. Thusly, ability to rewire cooperative communications within 14-3-3 ζ offers opportunity for novel drug discovery.

Kinesin-1–syntaphilin coupling mediates activity-dependent regulation of axonal mitochondrial transport

Axonal mitochondria are recruited to synaptic terminals in response to neuronal activity, but the mechanisms underlying activity-dependent regulation of mitochondrial transport are largely unknown. In this paper, using genetic mouse model combined with live imaging, we demonstrate that syntaphilin (SNPH) mediates the activity-dependent immobilization of axonal mitochondria through binding to KIF5. In vitro analysis showed that the KIF5–SNPH coupling inhibited the motor adenosine triphosphatase. Neuronal activity further recruited SNPH to axonal mitochondria. This motor-docking interplay was induced by Ca2+ and synaptic activity and was necessary to establish an appropriate balance between motile and stationary axonal mitochondria. Deleting snph abolished the activity-dependent immobilization of axonal mitochondria. We propose an “Engine-Switch and Brake” model, in which SNPH acts both as an engine off switch by sensing mitochondrial Rho guanosine triphosphatase-Ca2+ and as a brake by anchoring mitochondria to the microtubule track. Altogether, our study provides new mechanistic insight into the molecular interplay between motor and docking proteins, which arrests axonal mitochondrial transport in response to changes in neuronal activity.

Gab Docking Proteins in Cardiovascular Disease, Cancer, and Inflammation

The docking proteins of the Grb2-associated binder (Gab) family have emerged as crucial signaling compartments in metazoans. In mammals, the Gab proteins, consisting of Gab1, Gab2, and Gab3, are involved in the amplification and integration of signal transduction evoked by a variety of extracellular stimuli, including growth factors, cytokines, antigens, and other molecules. Gab proteins lack the enzymatic activity themselves; however, when phosphorylated on tyrosine residues, they provide binding sites for multiple Src homology-2 (SH2) domain-containing proteins, such as SH2-containing protein tyrosine phosphatase 2 (SHP2), phosphatidylinositol 3-kinase regulatory subunit p85, phospholipase Cγ, Crk, and GC-GAP. Through these interactions, the Gab proteins transduce signals from activated receptors into pathways with distinct biological functions, thereby contributing to signal diversification. They are known to play crucial roles in numerous physiological processes through their associations with SHP2 and p85. In addition, abnormal Gab protein signaling has been linked to human diseases including cancer, cardiovascular disease, and inflammatory disorders. In this paper, we provide an overview of the structure, effector functions, and regulation of the Gab docking proteins, with a special focus on their associations with cardiovascular disease, cancer, and inflammation.

The versatile molecular complex component LC8 promotes several distinct steps of flagellar assembly

LC8 is present in various molecular complexes. However, its role in these complexes remains unclear. We discovered that although LC8 is a subunit of the radial spoke (RS) complex in Chlamydomonas flagella, it was undetectable in the RS precursor that is converted into the mature RS at the tip of elongating axonemes. Interestingly, LC8 dimers bound in tandem to the N-terminal region of a spoke phosphoprotein, RS protein 3 (RSP3), that docks RSs to axonemes. LC8 enhanced the binding of RSP3 N-terminal fragments to purified axonemes. Likewise, the N-terminal fragments extracted from axonemes contained LC8 and putative spoke-docking proteins. Lastly, perturbations of RSP3’s LC8-binding sites resulted in asynchronous flagella with hypophosphorylated RSP3 and defective associations between LC8, RSs, and axonemes. We propose that at the tip of flagella, an array of LC8 dimers binds to RSP3 in RS precursors, triggering phosphorylation, stalk base formation, and axoneme targeting. These multiple effects shed new light on fundamental questions about LC8-containing complexes and axoneme assembly.