Physiology 3140A Lecture Notes - Lecture 10: Lamellipodium, Atp Hydrolysis, Microvillus

• School: Western University
• Department: Physiology
• Course: Physiology 3140A
• Professor: John Di Guglielmo

Document Summary

Network of protein fibers that extend throughout the cytoplasm. Many functions: cell adhesion and movement (migration, cell shape and structure, endocytosis/exocytosis (secretion and recycling) Microtubules become highways for endosomes: organelle/protein transport, mitosis/cytokinesis, cilia and flagella, muscle contraction. Polymer of and tubulin dimer (basic subunit) Gtp-binding subunits come together in proto-filaments (lines) to form hollow tubes. Dynamic instability: balance between assembly (polymerization) and disassembly (catastrophe) and reassembly (rescue, dependent on subunit critical concentration and temperature, dependent on gtp- -tubulin cap. Tubulin within mt hydrolyze gtp to gdp. Major mtoc in cells: mtoc = microtubule organizing center. Negative ends of microtubules are at mtoc and positive ends grow towards the cell periphery. The mtoc is usually found close to the nucleus. Phosphorylated maps detach from mts causing instability catastrophe: map-kinases phosphorylate maps. +tips (mt + end tracking proteins) e. g. eb1 (end binding protein 1) Possibly stabilize mts to reduce catastrophe (cap the + end; prevent gtp hydrolysis)