, 2007). Golgi outposts, hallmark of the satellite secretory pathway in dendrites, move anterogradely and retrogradely during extension and retraction of terminal dendrites, respectively. Arborization in the distal field demands active transport systems mediated by microtubule-based motors, as mutations in dynein light intermediate chain (dlic) or kinesin heavy chain (khc) fail to elaborate branches in the distal region of class

IV ddaC neurons. ( Satoh et al., 2008 and Zheng et al., 2008b). The transport of Rab5-positive endosomes allows branching of distal dendrites, suggesting that the endocytic pathway also has a role in dendrite morphogenesis ( Satoh et al., 2008). The growth of higher-order dendrites seems to require elevated level of endocytosis. Endocytosis is more active in dendrites than in axons in cultured hippocampal neurons. Dynamic assembly and selleck screening library disassembly of clathrin-positive structures, indicative of active endocytosis, are seen at dendritic shafts and tips of young hippocampal neurons. These clathrin-positive structures become stabilized in mature neurons (Blanpied et al., 2002). Endocytosis is known to regulate the polarized distribution of the cell adhesion molecule NgCAM http://www.selleckchem.com/products/KU-55933.html in hippocampal neurons, which is first transported to the somatodendritic membrane

and then transcytosed to the axonal surface (Yap et al., 2008). Endocytosis is also important for transporting NMDAR to synaptic sites during their formation in dendrites of young cortical neurons. The NMDAR packets transported along microtubules are intermittently exposed to the membrane surface by cycles of exocytosis and endocytosis, at sites coinciding with the clathrin “hotspots” (Washbourne et al., 2004). Endocytosis can regulate the activities of transmembrane receptors whose signaling activity is important to dendrite growth and maintenance (McAllister, 2002). For instance, the neurotrophin-Trk receptor-mediated signaling that

Olopatadine depends on endocytosis could be important for dendrite morphogenesis (Zheng et al., 2008a). However, how endocytosis regulates dendrite morphogenesis is not yet clear. Clathrin-mediated endocytosis (CME) is the major route for selectively internalizing extracellular molecules and transmembrane proteins from the plasma membrane. Transmembrane cargos destined for internalization are recruited into clathrin-coated pits through interaction with appropriate clathrin adaptors. One such accessory factor is adaptor protein 2 (AP2), a heterotetrameric complex consisting of α, β, μ, and σ subunits (Conner and Schmid, 2003). AP2-dependent cargo recruitment can be regulated by reversible protein phosphorylation by actin-related kinase (Ark) family serine/threonine kinases (Smythe and Ayscough, 2003).