Microtubules Essay Example | Topics and Well Written Essays - 1500 words

Microtubules - Essay Example Microtubules Again, these mechanisms need further exploration but the existing understanding is that reorganization of F-actin causes destabilization of transinteraction between TJ and AJ proteins of the adjacent epithelial cells and in turn initiate AJC internalization. Microtubules, which are also an important element of intracellular cytoskeleton have also been found to be closely related to the cell movement as a whole or any intracellular structure formation like, vesiscles and their movement. Data support the abundance of microtubules in differentiated renal and intestinal cells and depolymerization of microtubules leading to disruption of the integrity of TJs and Ajs in some tissues like lungs. This evidence led the author to explore the role of microtubules depolymerization in the disruptions of apical junction complex. Existing evidence strongly support the role of microtubules depolymerization in the disruption of intercellular connections like tight junctions and adherens junction in various tissues and helps in the pathogenesis of various disease processes. In this regard it has been shown that the endothelial intercellular junctions are also disassembled as well as others like in the brain. Building a rationale on the basis of these data, author formulated a hypothesis: ‘microtubules are involved in the disruption of apical junctions in simple epithelial cells’.... 'Disassembly of the AJC in calcium depleted SK-CO-15 cells is dependent on microtubule integrity;' 'Inhibition or attenuation of AJC disassembly by microtubule stabilization would indicate the role for dynamic microtubules in the process;' 'Polarity of perijunctional microtubules would dictate the type of microtubule motor which is involved in disassembly and internalization of the AJC.' To test these hypotheses, the author carried out a research study where a number of experimental activities were carried out, like: use of antibodies for the detection of intercellular junctions, while microtubules were detected by immunoflurescence labeling and Western Blotting. Cell culture was used was SK-CO-15, which is a transformed human colonic epithelial cell line. To make the medium free from Ca++, the monolayers of epithelium were washed with calcium free-Eagle's minimum essential medium for suspension culture. Pharmacological agents utilized were; nocodazole; docetaxel and pacitaxel; adenylimidodiphosphate (AMP-PNP) and aurintriccarboxyylic acid (ATA). Major findings Through this experiment, the author has been able to demonstrate the role of microtubules depolymerization in the disassembly of junctional complexes through a variety of experimental evidence. Disassembly of the AJC in calcium depleted SK-CO-15 cells To answer the research question related to first sub-hypothesis, the findings have been: At normal Ca++ concentrations, depolymerized microtubules with nocodazole TJ and AJ proteins were found to be located at the cell-cell contacts, reflecting chicken-wire staining pattern while in the environment with depletion of Ca++ for one hour the result was disruption of AJs and TJs with accumulation of e-cadherin, occluding and ZO-1 in