INTRODUCTION Hedgehog signaling has been implicated as playing crucial roles in the control of cell growth and patterning during embryonic development and other physiological processes in both Drosophila and vertebrates. Given these important physiological roles, it was of no surprise that disruption of Hh signaling was found to be the underlying cause of numerous human developmental disorders and that perturbations of Hh signaling play a causative or facilitating role in many human cancers (5–7 Cell Network). Motivated by the important role Hh has in cancer, researchers are trying to unlock the still largely unknown mechanistic understanding of Hh signal transduction. Hh signaling is transduced through a series of molecular interactions …show more content…
showed that phosphorlyation is not neccessary for Smo translocation but rather inhibition of Smo endocytosis was sufficient to drive Smo to the plasma membrane. This was observed by fluorescently labelling Smo with GFP and tracking its location following either treatment with Hh or Dynasore, a pharmacological inhibitor of dynamin-mediated endocytosis (Macia et al., 2006). In both cases Smo translocated to the plasma membrane. The same was done for a nonphosphorylatable SmoSA-GFP fusion in which the inhibition of endocytosis by treatment with Dynasore caused SmoSA to translocation to the plasma membrane. The observation that SmoSA can also be present at the membrane demonstrates that some exchange between the intracellular and plasma membrane bound pools must also occur for nonphosphorylated …show more content…
Additionally, inactivation of Ptc is sufficient to increase levels of this phospholipid (Yavari et al., 2010). These observations support an ‘endocytosis’ model of Hh pathway activation, whereby inactivation of Ptc primarily affects Smo redistribution to the plasma membrane, presumably by regulating the local lipid content of either the plasma membrane or Smo containing endosomes. This suggests Ptc inactivation by Hh first drives Smo membrane localisation by modulating membrane phospholipids, with Smo phosphorylation and clustering occurring
Hyperplasia is the early stage development of cells to cancer cells. It increases in cells that have the capability to proliferate at a fast rate. Often times, hyperplasia is correlated with the increase in proliferation and the speed of mitosis. The increase in the number of cells with hyperplasia means that the proliferation is happening at a faster rate than normal. Hyperplasia is considered to be the early stage of dysplasia, though not all hyperplasia leads to dysplasia.
The one concept that I feel is most significant in this week’s reading would be the Hedgehog Concept, simplifying a complex world into a single organized idea/principle that guides everything else.
This occurs when special carrier proteins carry solutes dissolved in the water across the membrane by using active transport. When the concentration gradient can not allow travel from one side of the membrane to the other fast enough for the cell’s nutritional needs, then facilitated diffusion is used. The transport protein is specialized for the solute it is carrying, just as enzymes are specialized for their substrate. The transport protein can be
The underlying purpose of the experiments performed in the study, Promoter Hypermethylation of KLF4 Inactivates its Tumor Suppressor Function in Cervical Carcinogenesis, is to investigate the mechanism by which the KLF4 gene is silenced in cervical carcinomas. Cervical cancer accounts for 250,000 female deaths every year. Developing therapies for cervical cancer has been limited due to the lack of genetic and epigenetic data of the mechanism causing the cancer. The KLF4 gene is a transcriptional regulator of cell growth and differentiation. It functions as a tumor suppressor in cervical cancer, but is found to be inactivated in cervical cancer. The overexpression of KLF4 protein is known to inhibit cervical cancer cell growth and tumor formation by activating a cell cycle suppressor. Promoter CpG island hypermethylation can result in transcriptional silencing of many tumor suppressing genes. Two CpG regions, BSQ1 and BSQ3, were examined in this experiment.
Once binding has occurred, a cascade of signalling reactions will initiate, with Rho guanosine-5'-triphosphate (Rho GTPases) such as rho-asso...
“The plasma membrane is the edge of life, the boundary that separates the living cell from its nonliving surroundings. The plasma membrane is a remarkable film, so thin that you would have to stack 8,000 of these membranes to equal the thickness of the page you are reading. Yet the plasma membrane can regulate the traffic of chemicals into and out of the cell. The key to how a membrane works is its structure” (Simon, 02/2012, p. 60).
Cancer starts when certain cells in the body are mutated or changed and begin to divide. Cancerous cells grow differently than normal cells, instead of progressing through the normal cell lifecycle, cancer cells continue to grow and create more abnormal cells. A specific trait of cancer cells is that they have the ability to infiltrate and grow into surrounding tissues, developing out of control and causing serious damage to the host (Vincent, 2008). Cells become cance...
The cell plasma membrane, a bilayer structure composed mainly of phospholipids, is characterized by its fluidity. Membrane fluidity, as well as being affected by lipid and protein composition and temperature (Purdy et al. 2005), is regulated by its cholesterol concentration (Harby 2001, McLaurin 2002). Cholesterol is a special type of lipid, known as a steroid, formed by a polar OH headgroup and a single hydrocarbon tail (Wikipedia 2005, Diwan 2005). Like its fellow membrane lipids, cholesterol arranges itself in the same direction; its polar head is lined up with the polar headgroups of the phospholipid molecules (Spurger 2002). The stiffening and decreasing permeability of the bilayer that results from including cholesterol occurs due to its placement; the short, rigid molecules fit neatly into the gaps between phospholipids left due to the bends in their hydrocarbon tails (Alberts et al. 2004). Increased fluidity of the bilayer is a result of these bends or kinks affecting how closely the phospholipids can pack together (Alberts et al. 2004). Consequently, adding cholesterol molecules into the gaps between them disrupts the close packing of the phospholipids, resulting in the decreased membrane fluidity (Yehuda et al. 2002).
The cell cycle is the process by which cells progress and divide. In normal cells, the cell cycle is controlled by a complex series of signaling pathways by which a cell grows, replicates it’s DNA and divides, these are called proto-oncogenes. A proto-oncogene is a normal gene that could become an oncogene due to mutations. This process has mechanisms to ensure that errors are corrected, if they are not, the cells commit suicide (apoptosis). This process is tightly regulated by the genes within a cell’s nucleus. In cancer, as a result of genetic mutations, this process malfunctions, resulting in uncontrolled cell proliferation. Mutations in proto-oncogene or in a tumour suppressor gene allow a cancerous cell to grow and divide without the normal control imposed by the cell cycle. A change in the DNA sequence of the proto-oncogene gives rise to an oncogene, which
As an inducer of HIF-1 production, it’s been used to study the apoptotic effects in HepG2 cells.
plasma membranes, meaning animals and plants contain lipids. In this paper I will display and
... information needed to stimulate normal cell growth. Failure can lead to the onset of cancer. (Campbell, Reece, Urry, Cain, Wasserman, Minorsky and Jackson, 2008)
There are many functions lipids have. One of the main functions lipids are structural components in the cell. Lipids make up approximately 50% of the mass of most cell membranes. The lipids that are found in the cell membrane are called phospholipid. Phospholipid are the predominant lipids of cell membrane. Phospholipids aggregate or self-assemble when mixed with water, but in a different manner than the soaps and detergents. Because of the two pendant alkyl chains in phospholipids and the unusual mixed charges in their head groups, micelle formation is unfavorable relative to a bilayer structure.
4) Human Growth Hormone (HGH) which affects many target cells and stimulates their reproduction, growth and repair.
Plasma membrane is made up of two layers of phospholipids which are a class of lipids and has many proteins embedded in it. The proteins have a function of providing support and shape to a cell. There are three different proteins in cell membranes (see appendix 1). The plasma membrane also regulates the entry and exit of the cell, as many molecules cross the cell membrane by osmosis and Prokaryotes include several kinds of microorganisms, such as bacteria and cyanobacteria. Eukaryotes include microorganisms as fungi, protozoa, and simple algae.