BIO130H1 Lecture Notes - Lecture 20: Atp Hydrolysis, Kinesin, Dynein

109 views6 pages
School
Department
Course
Professor

For unlimited access to Class Notes, a Class+ subscription is required.

BIO130 – Lecture 20 – Actin Filaments
Thursday, March 24 th
, 2016
Nerve Cells
-Nerve cells in your spinal cord extend to your finger tips
oThese neurons can be a meter long
-Problem: how does neurotransmitter synthesized in the ER get to the synapse?
oThe kinesin protein!
“Walky guys”
-The ER and Golgi are located in the cell body
Kinesin
-A motor protein that “walks” along microtubules
-One foot in front of the other
-The two types of proteins that make up these proteins:
oKinesin and dynein
Axonal Vesicular Transport
-Dynein movement
oTowards the cell body
The microtubule minus end
-Kinesin movement
oTowards the axon terminus
The microtubule plus end
Movement of Vesicles Through the Endomembrane System
-ER, Golgi, and plasma membrane
oNote you can move vesicles as well as other organelles
oMinus end facing golgi, plus end facing plasma membrane
-You can move peroxisomes and mitochondria around in the cell
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in
Transfer Glucose
-From the intestine to the blood stream
-Review from previous lecture
-Epithelial cells
-Apical end and basolateral ends
oTransmembrane proteins made in ER membrane then transporter
Therefore, this requires kinesin or dynein
Microfilaments/Actin Filaments
-Involved in:
oCell motility (crawling)
oContractile activity
oCytokinesis
-Made of:
oActin monomers
oFlexible
oInextensible
oHelical filaments
-Motor protein:
oMyosin
oNot kinesin or dynein
-Can make, among other things, contractile bundle, gel-like network, or tight
parallel bundle
The Structure of Actin Filaments
-Composed of a single type of globular protein
oActin monomers
oTwo protofilaments twisted in a right-handed helix
-Are actin filaments polar?
oYes!
oDue to regular orientation of actin monomers in each protofilament
Head to tail arrangement of actin monomers
Actin Monomers
-Free monomers are bound to ATP
oATP is bound in the centre of the protein
-There is a C- and N-terminus, therefore polar
-Plus end and minus end do not refer to charge
-Actin is an ATP-ase
oHydrolyses ATP
ADP remains bound
-ATP hydrolysis occurs more rapidly after actin monomers have been
incorporated into the filament
-Growth of the filament is faster at the plus end
oActin filaments have an ATP cap
-Compared to microtubules, we have monomers in actin
oHeterodimers in microtubules
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in

Get access

Grade+
$10 USD/m
Billed $120 USD annually
Homework Help
Class Notes
Textbook Notes
40 Verified Answers
Study Guides
1 Booster Class
Class+
$8 USD/m
Billed $96 USD annually
Homework Help
Class Notes
Textbook Notes
30 Verified Answers
Study Guides
1 Booster Class