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Actin-binding Protein - Spectrin

Spectrin is a cytoskeletal protein that lines the intracellular side of the plasma membrane of many cell types in pentagonal or hexagonal arrangements, forming a scaffolding and playing an important role in maintenance of plasma membrane integrity and cytoskeletal structure.The hexagonal arrangements are formed by tetramers of spectrin associating with short actin filaments at either end of the tetramer. These short actin filaments act as junctional complexes allowing the formation of the hexagonal mesh.

In certain types of brain injury such as diffuse axonal injury, spectrin is irreversibly cleaved by the proteolytic enzyme calpain, destroying the cytosketelon. Spectrin cleavage causes the membrane to form blebs and ultimately to be degraded, usually leading to the death of the cell.


History

Function

Homework

Lecture 4 - Nucleus - What did you find interesting and did not know about the nucleus?


From the nucleus lecture, I have learnt that the nucleus consists of two concentric membranes, which form the nuclear envelope. It was interesting to know that they break down during mitosis and also contain nuclear pores that make them permeable.


Lecture 5 - Exocytosis - What concept about exocytosis did you find difficult to understand?


Lecture 7 - Mitochondria - What types of cellular processes require lots of energy from the mitochondria?


The mitochondria produce energy (ATP) using energy that is stored in food by aerobic respiration. After glycolysis, pyruvate enters the mitochondrion to enter the Krebs cycle in order to complete the oxidation of organic fuel and finally produce ATP. Cellular processes such as signaling of cells, transportation of cells across cell membranes, cell differentiation, biosynthesis and locomotion require large amounts of the energy produced from the mitochondria.


Lecture 8 - Adhesion - What do the different "CAM" acronyms stand for?


CAM - cell adhesion molecules

Ng-CAM stands for Neuroglia Cell Adhesion Molecule

I-CAM stands for Intercellular Cellular Adhesion Molecule

L-CAM stands for Liver Cell Adhesion Molecule


Lecture 10 - What is the name of the epidermal layer between the basal and granulosa layer and how does it relate to intermediate filaments?


The name of the epidermal layer between the basal and granulosa layer is called the stratum spinosum. Intermediate filaments are synthesized by cells of the stratum spinosum. These filaments help support the structure and also resists abrasion of the skin.


Lab 6 - "If you've seen differences in the distribution of phenotypes in Tm4 over-expressing B35 cells versus control B35 cells, describe these differences. Formulate a hypothesis with regards to what changes on the molecular level may have occurred due to the over-expression of Tm4 that lead to morphological changes that you have observed"


Lecture 14 - Confocal Microscopy - What are the 2 main forms of generating confocal microscopy?


Lecture 15 - Cell Cycle - What does "S" stand for in the S phase?


The S phase stands for the synthesis phase. It occurs during interphase in between G1 phase and the G2 phase.