Increased phosphorylation of the KIF5 anterograde motor is associated with impaired axonal transport and neurodegeneration, but paradoxically also with normal transport, though the details are not fully defined. JNK phosphorylates KIF5C on S176 in the motor domain; a site that we show is phosphorylated in brain. Microtubule pelleting assays demonstrate that phosphomimetic KIF5C(1-560)(S176D) associates weakly with microtubules compared to KIF5C(1-560)(WT).
View Article and Find Full Text PDFCell migration is a fundamental biological function, critical during development and regeneration, whereas deregulated migration underlies neurological birth defects and cancer metastasis. MARCKS-like protein 1 (MARCKSL1) is widely expressed in nervous tissue, where, like Jun N-terminal protein kinase (JNK), it is required for neural tube formation, though the mechanism is unknown. Here we show that MARCKSL1 is directly phosphorylated by JNK on C-terminal residues (S120, T148, and T183).
View Article and Find Full Text PDFThe common lymphatic endothelial and vascular endothelial receptor (CLEVER-1; also known as FEEL-1 and stabilin-1) is a recycling and intracellular trafficking receptor with multifunctional properties. In this study, we demonstrate increased endothelial expression of CLEVER-1/stabilin-1 at sites of leukocyte recruitment to the inflamed human liver including sinusoids, septal vessels, and lymphoid follicles in inflammatory liver disease and tumor-associated vessels in hepatocellular carcinoma. We used primary cultures of human hepatic sinusoidal endothelial cells (HSEC) to demonstrate that CLEVER-1/stabilin-1 expression is enhanced by hepatocyte growth factor but not by classical proinflammatory cytokines.
View Article and Find Full Text PDFCell migration is the consequence of the sum of positive and negative regulatory mechanisms. Although appropriate migration of neurons is a principal feature of brain development, the negative regulatory mechanisms remain obscure. We found that JNK1 was highly active in developing cortex and that selective inhibition of JNK in the cytoplasm markedly increased both the frequency of exit from the multipolar stage and radial migration rate and ultimately led to an ill-defined cellular organization.
View Article and Find Full Text PDFLoss-of-function mutations in the IKBKAP gene, which encodes IKAP (ELP1), cause familial dysautonomia (FD), with defective neuronal development and maintenance. Molecular mechanisms leading to FD are poorly understood. We demonstrate that various RNA-interference-based depletions of IKAP lead to defective adhesion and migration in several cell types, including rat primary neurons.
View Article and Find Full Text PDFBackground: Cell stress and tissue injury lead to c-Jun N-terminal kinase (JNK) activation, which is known to contribute to cell death. Paradoxically, strong evidence supports an important role for JNK in the regeneration of neuronal processes, subsequent to injury.
Objective: Recent research revealed the growth cone-associated protein superior cervical ganglion-10 protein as a candidate effector for the regeneration pathway mediated by JNK1.