RESUMEN
Mutations in mammalian Lis1 (Pafah1b1) result in neuronal migration defects. Several lines of evidence suggest that LIS1 participates in pathways regulating microtubule function, but the molecular mechanisms are unknown. Here, we demonstrate that LIS1 directly interacts with the cytoplasmic dynein heavy chain (CDHC) and NUDEL, a murine homolog of the Aspergillus nidulans nuclear migration mutant NudE. LIS1 and NUDEL colocalize predominantly at the centrosome in early neuroblasts but redistribute to axons in association with retrograde dynein motor proteins. NUDEL is phosphorylated by Cdk5/p35, a complex essential for neuronal migration. NUDEL and LIS1 regulate the distribution of CDHC along microtubules, and establish a direct functional link between LIS1, NUDEL, and microtubule motors. These results suggest that LIS1 and NUDEL regulate CDHC activity during neuronal migration and axonal retrograde transport in a Cdk5/p35-dependent fashion.
Asunto(s)
Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Dineínas/metabolismo , Proteínas Asociadas a Microtúbulos/metabolismo , Sistema Nervioso/metabolismo , 1-Alquil-2-acetilglicerofosfocolina Esterasa , Animales , Aspergillus nidulans , Transporte Axonal/fisiología , Movimiento Celular , Células Cultivadas , Centrosoma/metabolismo , Quinasa 5 Dependiente de la Ciclina , Quinasas Ciclina-Dependientes/metabolismo , Citoplasma/metabolismo , Proteínas Fúngicas/genética , Humanos , Sustancias Macromoleculares , Ratones , Ratones Mutantes , Proteínas Asociadas a Microtúbulos/genética , Microtúbulos/metabolismo , Datos de Secuencia Molecular , Sistema Nervioso/citología , Sistema Nervioso/embriología , Neuronas/citología , Neuronas/metabolismo , Fosforilación , Subunidades de Proteína , Homología de Secuencia de Aminoácido , Células Madre/citología , Células Madre/metabolismo , Técnicas del Sistema de Dos HíbridosRESUMEN
The ergometer can be a versatile means of measurement if attachments are developed for special purposes or if attachment is developed for multi-uses. In this study, an ergometer attachment for the measurement of power was designed and the measurement of power and the maximum anaerobic power in swimming was tested. A rotation drum was attached to one pedal of an ergometer. The rotation of this drum was synchronized with the rotation of the pedal. One end of a wire for a traction by a swimmer was connected to the drum. The other end of the wire was attached to a belt around the waist of a swimmer. The swimmer swam at full strength, thus causing the drum to rotate. The rotational velocity of the drum was detected as voltage by a magnetic permanent motor and transformed to wire tractional velocity; this velocity was equal to swimming velocity. The wire tension (= load) was controlled by a load adjusting lever of the ergometer. This wire tension was equal to the load which was added to the swimmer. The power calculation was based on a curved regression equation approximated from the load and the velocity. This equation was shown as follows; (P + a) (v + b) = (P0 + a)b or its development (P + a)v = b(P0 - P) and provided that P: force or load, v: swimming velocity, P0: maximum tractional force, a and b: constants. This ergometer attachment made it possible to measure and evaluate the power and the maximum anaerobic power in swimming with ease and at low cost. Measurement and evaluation are easily performed using the system, which is just one example of the possible applications of the ergometer.