Non-enzymatic Protein Function (5/15) Flashcards
Cytoskeleton function
Shape and structure
Motion
Cell division
Organelle and biomolecule transport
Actin
forms the microfilaments of the cytoskeleton and is very abundent
Actin in microfilaments: function
motion
structure
cell division
muscle contraction
Individual actin monomers
G-actin because they have a globular shape and posses a site where ATP or ADP can bind
When a ton of G-actin bind together…
It forms F-actin which stands are filamentous actin and two of these stick together to form a microfilament
Rapid growth and disassembly
when polymerization= depolymerization, we have tread-milling and when we want to stop, we have capping proteins
Intermediate filaments
a long alpha-helical section
very flexible: can be stretched
Where are intermediate filaments found?
in the cytoplam
What is the main function of intermediate filaments?
structural support
cell adhesion
organelle positioning
Microtubules
structural support for cilia and eukaryotic flagella
chromosome separation during mitosis and meiosis
intracellular transport
Subunit of microtubules
tubulin dimer consisting of an alpha-tubulin and a beta-tubulin
bring GTP or GDP
Motor protein functions
transport
motility
muscle contraction
Kinesins
ATP-ases
consumes energy from ATP hydrolysis
Direction of kinesins
move to + end of microtubules which is to the periphery and this is called anterograde transport
Make up of kinesins
heterotretramers
made of of 4 subunits that are not all the same
2 subunits: heavy chains, with two head groups that are the feet
2 other subunits: light chains
How kinesins move
ATP binds head to the microtubule causing a conformational change and swing with other head bound to ADP forward (ADP has head be detacted)