Eukaryotic Cell Motility

Microtubule-Based Motility via Cilia or Flagella

Table of Contents

Eukaryotic Cells1

Functions of Microtubules2

Motility3

Cilia3

Structure3

Movement4

Coordination and Control4

Flagella6

Structure6

The Growth of the Flagella7

Evolution7

Microtubule-Based Motility via Flagella8

Microtubule-Based Motility via Cilia or Flagella

Eukaryotic Cells

The observation of the cell in three dimensions reveals interconnections between filamentous protein structures within the cytoplasm of eukaryotic cells. These structures form a cytoskeleton, the cytoskeleton, which maintains the organization of the cell, allows move, position their organelles and directs intracellular traffic of vesicles and different materials. It has identified three different types of filaments as key members of the cytoskeleton: the microtubules, microfilaments (actin filaments mainly) and intermediate filaments (Butler & Tolic, 2002, 595-605).

Cell motility is one of the greatest achievements of evolution and the cytoskeleton, system cytoplasmic fibers, essential component of support for this process and transport guide intracellular organelles and other elements. Its early appearance in evolution can be seen by genomics and structural similarity in Bacteria and Archaea, proteins MreB and actin MB1 with of eukaryotes (Charest, 2007, 377-390).

In microtubule biology, tubular structure composed of tubulin protein, present in eukaryotic cells. It participates in the formation of the cytoskeleton, responsible for the structure and cell shape, cell motility, the formation of the mitotic spindle and the intracellular translocation of lysosomes and other organelles. They are rod cables of varying lengths; the outer diameter is 24 nm, 14 nm of the inner. They consist of two types of globular proteins, the a-tubulin and ß-tubulin, each of molecular weight 55,000, associated aß dimers. The dimers bind head-tail sequences and form the long protofilaments, 13 parallel protofilaments are arranged side by side to form the single microtubule (Dembo, 1996, 2008-2022).

Microtubules and motor proteins Microtubules are polymers of the protein tubulin, a heterodimer of a and ß tubulin about 55 kD, also highly conserved sequences. These proteins bear a large homology with the bacterial protein FtsZ plays an important role in cell division.

Globular proteins can also be grouped into tiny hollow tubules that act as structural framework of cells and at the same time, transport substances from one part of the cell to another. Each of these microtubules is formed by two types of protein molecules almost spherical, is arranged in pairs and is joined at the growing end of microtubules and increases its length depending on the needs. Microtubules are also the internal structure of the cilia and flagella, membrane appendages which serve some microorganisms to move (Dembo & Wang, 1999, 2307-2316).

Microtubules are responsible for the movement of cilia and flagella and movement intracellular vesicles. This is the result of polymerization and depolymerization of microtubules and the action of motor proteins. In some cases, cell movements are due to both mechanisms (eg, separation of chromosomes during meiosis).

Several cell movements depend on the interaction between actin filaments and motor protein myosin, a Suitable moving along actin filaments coupled to the ATP hydrolysis to conformational changes. The genomic analysis showed that several highly conserved genes, especially in the region responsible for the "motor".

Functions of Microtubules

Determination of cell ...