Class Notes (810,290)
Canada (494,047)
Brock University (11,931)
Biology (1,612)
BIOL 2P03 (65)
Lecture 8

BIOL 2P03 Lecture 8: Week 8 Screencast - Cell Organization and Movement- Microfilaments II

5 Pages
Unlock Document

Brock University
Mark K Lukewich

BIOL 2P03 Week 8 Screencast – Cell Organization and Movement: Microfilaments II th th March 6 – March 12 , 2017 Cell Movement Overview • Cellular contents often need to be moved from one location of the cell to another – Endocytic vesicles transported to lysosomes – Exocytotic vesicles transported to plasma membrane – Duplicated chromosomes transported to opposite poles of cell during mitosis • Cells can also move through their environment – Immune cells migrating to regions containing micro-organisms – Fibroblasts migrating to injured tissues • The cytoskeleton plays an important role in cell movement • Microfilament assembly/disassembly can be used to cellular structures that are attached to F-actin • Microfilaments and microtubules are also used as tracks for motor proteins – These motor proteins move along microfilaments and microtubules to transport their cargo Microfilaments II: Movement of Cellular Cargo by Actin-based Motor Proteins Myosin • Myosin is a motor protein associated with the microfilament system of the cytoskeleton • Myosin can bind to actin and uses energy from ATP hydrolysis to move actin filaments • Myosin is a multimeric protein consisting of heavy and light chains • Each myosin heavy chain contains • A head region that is able to bind to actin and ATP/ADP and possesses an intrinsic ATPase • A tail region that determines what cargo can be carried and helps form myosin dimers • A neck region bound to myosin light chains Myosin-based Movement • Myosin uses ATP hydrolysis to fuel the movement of actin in a defined sequence of events • Myosin that is not bound to ADP/ATP is tightly bound to F-actin • (1) When ATP binds to myosin, it releases F-actin • (2) ATP is then hydrolyzed which causes the myosin head to extend away from the tail region • ‘cocked’ position • (3) The myosin head, now containing ADP and Pi, binds to actin • (4) Pi is released from myosin and the head bends toward the tail region, pulling actin in this direction – ‘Power stroke’ • (5) ADP is then released from myosin – Myosin binds tightly to actin • Once ATP binds, myosin releases actin and another cycle begins • There are three common classes of myosin, each of which has a slightly different structure and primary
More Less

Related notes for BIOL 2P03

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.