DishevelledDishevelled (Dsh) is a family of proteins involved in canonical and non-canonical Wnt signalling pathways. Dsh (Dvl in mammals) is a cytoplasmic phosphoprotein that acts directly downstream of frizzled receptors. It takes its name from its initial discovery in flies, where a mutation in the dishevelled gene was observed to cause improper orientation of body and wing hairs. There are vertebrate homologs in zebrafish, Xenopus (Xdsh), mice (Dvl1, -2, -3) and humans (DVL-1, -2, -3).
Reverse transportReverse transport, or transporter reversal, is a phenomenon in which the substrates of a membrane transport protein are moved in the opposite direction to that of their typical movement by the transporter. Transporter reversal typically occurs when a membrane transport protein is phosphorylated by a particular protein kinase, which is an enzyme that adds a phosphate group to proteins. The primary function of most neurotransmitter transporters is to facilitate neurotransmitter reuptake (i.e.
Lipid signalingLipid signaling, broadly defined, refers to any biological signaling event involving a lipid messenger that binds a protein target, such as a receptor, kinase or phosphatase, which in turn mediate the effects of these lipids on specific cellular responses. Lipid signaling is thought to be qualitatively different from other classical signaling paradigms (such as monoamine neurotransmission) because lipids can freely diffuse through membranes (see osmosis).
Son of SevenlessIn cell signalling, Son of Sevenless (SOS) refers to a set of genes encoding guanine nucleotide exchange factors that act on the Ras subfamily of small GTPases. The gene was so named because the Sos protein that it encoded was found to operate downstream of the sevenless gene in Drosophila melanogaster in a Ras/MAP kinase pathway. When sevenless is mutated or otherwise dysfunctional during development of the fly's ultraviolet light-sensitive compound eye, the seventh, central photoreceptor (R7) of each ommatidium fails to form.
Guanine nucleotide exchange factorGuanine nucleotide exchange factors (GEFs) are proteins or protein domains that activate monomeric GTPases by stimulating the release of guanosine diphosphate (GDP) to allow binding of guanosine triphosphate (GTP). A variety of unrelated structural domains have been shown to exhibit guanine nucleotide exchange activity. Some GEFs can activate multiple GTPases while others are specific to a single GTPase. Guanine nucleotide exchange factors (GEFs) are proteins or protein domains involved in the activation of small GTPases.
Vesicle fusionVesicle fusion is the merging of a vesicle with other vesicles or a part of a cell membrane. In the latter case, it is the end stage of secretion from secretory vesicles, where their contents are expelled from the cell through exocytosis. Vesicles can also fuse with other target cell compartments, such as a lysosome. Exocytosis occurs when secretory vesicles transiently dock and fuse at the base of cup-shaped structures at the cell plasma membrane called porosome, the universal secretory machinery in cells.
Asymmetric cell divisionAn asymmetric cell division produces two daughter cells with different cellular fates. This is in contrast to symmetric cell divisions which give rise to daughter cells of equivalent fates. Notably, stem cells divide asymmetrically to give rise to two distinct daughter cells: one copy of the original stem cell as well as a second daughter programmed to differentiate into a non-stem cell fate. (In times of growth or regeneration, stem cells can also divide symmetrically, to produce two identical copies of the original cell.
