#DENDRITE FACTS HOW TO#

Although the exocyst plays well-established roles in neuronal polarization and the regulation of neurite outgrowth ( Hazuka et al., 1999 Lalli and Hall, 2005 Murthy et al., 2003 Vega and Hsu, 2001), a role in dendrite development has not been specifically attributed to the exocyst. In the absence of a functional exocyst, secretory vesicles are delivered to the plasma membrane, but SNARE complexes do not form and exocytosis is blocked ( Grote et al., 2000). The exocyst is an evolutionarily conserved octameric protein complex that was originally identified in yeast based on its role in the spatial targeting and tethering of post-Golgi vesicles to specific sites of membrane expansion ( Novick et al., 1980 TerBush et al., 1996). In yeast, the SM protein Sec1 physically interacts with subunits of the exocyst to facilitate SNARE-complex assembly and membrane fusion upon vesicle arrival at the plasma membrane ( Morgera et al., 2012 Wiederkehr et al., 2004). Although it has been demonstrated that disrupting post-Golgi trafficking can impede dendrite growth ( Horton et al., 2005 Ye et al., 2007), little is known about the role that exocytosis specifically plays in dendritic morphogenesis. PPVs that are synthesized in the cell body are transported to growing axons ( Pfenninger and Johnson, 1983), and although the source for material to support dendrite growth is unclear, the polarized localization of satellite secretory pathways in dendrites suggests that PPVs might be locally generated in some dendrites ( Horton et al., 2005 Pfenninger, 2009 Ye et al., 2007). In de novo axon outgrowth, addition of new membrane occurs primarily through exocytosis of plasmalemmal precursor vesicles (PPVs) at the growth cone ( Bray, 1970 Craig et al., 1995 Lockerbie et al., 1991), which is mediated, in part, by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins ( Pfenninger, 2009). The addition of membrane proteins and lipids through exocytosis plays a fundamental role in this process, but growth in axons and dendrites appears to be regulated by distinct pathways. By contrast, membrane-associated proteins readily diffuse from primary dendrites into terminals, but not in the reverse direction, suggesting that diffusion, rather than targeted exocytosis, supplies membranous material for terminal dendritic growth, revealing key differences in the distribution of materials to these expanding dendritic compartments.Īxons and dendrites lengthen by several orders of magnitude during neuronal development, and this lengthening of neurites is essential for establishing the morphological features of a neuron that ultimately determine its connectivity and function. Rop promotes dendrite growth together with the exocyst, an octameric protein complex involved in tethering vesicles to the plasma membrane, with Rop–exocyst complexes and exocytosis predominating in primary dendrites over terminal dendrites. Neurons with depleted Rop function exhibit reduced terminal dendrite outgrowth followed by primary dendrite degeneration, suggestive of differential requirements for exocytosis in the growth and maintenance of different dendritic compartments. Here, we report that Ras opposite ( Rop), the Drosophila ortholog of the key exocytosis regulator Munc18-1 (also known as STXBP1), is an essential factor mediating dendrite growth. Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.Dendrites lengthen by several orders of magnitude during neuronal development, but how membrane is allocated in dendrites to facilitate this growth remains unclear.Britannica Beyond We’ve created a new place where questions are at the center of learning.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.

#DENDRITE FACTS HOW TO#

COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.

Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.

Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions.

This Time in History In these videos, find out what happened this month (or any month!) in history.#WTFact Videos In #WTFact Britannica shares some of the most bizarre facts we can find.Demystified Videos In Demystified, Britannica has all the answers to your burning questions.Britannica Classics Check out these retro videos from Encyclopedia Britannica’s archives.

Dendrite facts