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Benjamin Adam Samuels

Publications and source records attributed to Benjamin Adam Samuels.

4 recordsLinked to original sources
PubMed2006

Cyclin-dependent kinase 5 permits efficient cytoskeletal remodeling--a hypothesis on neuronal migration.

Migration of neurons to their proper position underlies mammalian brain development. To remain on the proper path, a migrating neuron needs to detect various external signals and respond by efficiently remodeling its cytoskeleton. Cyclin-dependent kinase 5 (Cdk5), a member of the cyclin-dependent kinase family, regulates neuronal migration by phosphorylating a number of intracellular substrates. Deficiencies in Cdk5 preferentially cause impairments in radial glia-guided migration, a process that involves complex remodeling of the cytoskeleton, particularly the microtubules. Furthermore, the defined substrates of Cdk5 that are important for migration generally link Cdk5 to the cytoskeleton. Interestingly, none of these phosphorylation events seem to directly control the activity of the substrates. Taken together, these findings support a model in which Cdk5 does not directly control the detection of any specific external signals but instead regulates efficient remodeling of the cytoskeleton through phosphorylation of multiple substrates.

Aging↗
PubMed2003

Serine 732 phosphorylation of FAK by Cdk5 is important for microtubule organization, nuclear movement, and neuronal migration.

The serine/threonine kinase Cdk5 plays an essential role in neuronal positioning during corticogenesis, but the underlying mechanisms are unknown. In nonneuronal cells, the tyrosine kinase FAK is a major regulator of cell motility through focal adhesions. It is unclear whether FAK plays a role in brain development. Here, we show that FAK phosphorylation by Cdk5 at S732 is important for microtubule organization, nuclear movement, and neuronal migration. In cultured neurons, S732-phosphorylated FAK is enriched along a centrosome-associated microtubule fork that abuts the nucleus. Overexpression of the nonphosphorylatable mutant FAK S732A results in disorganization of the microtubule fork and impairment of nuclear movement in vitro, and neuronal positioning defects in vivo. These observations are reminiscent of what is seen in the Cdk5-deficient mice. Taken together, these results suggest that Cdk5 phosphorylation of FAK is critical for neuronal migration through regulation of a microtubule fork important for nuclear translocation.

Animals↗