Cell cortex and locomotion Flashcards Preview

MCBL > Cell cortex and locomotion > Flashcards

Flashcards in Cell cortex and locomotion Deck (19):
1

Where are actin filaments found in the cell?

throughout the cytoplasma, but concentrated ina region just below the plasma membrane in most cells

2

What is the cell cortex?

actin filaments are crossed linked into a supportive and strengthening network
gives cell their characteristic shape

3

What are actin filaments attached to the plasma membrane by?

various linker proteins

4

what are the Crawling cells?

fibroblats
amoeba
neutrophils

5

Why do crawling cells reorganize their cell cortex?

utilize their MF and their interaction with other proteins to move

6

What is the leading edge?

front of moving cell , composed of two structures

7

What are the two structures of the leading edge?

lamellipodia
filopodia

8

What is the lamellipodia?

thin sheet like structure with dense network of F-actin in a single orientation with plus end at plasma membrane

9

What is the filopodia?

exporatory fibers, long thin with parallel bundles of 10-20 F-actin

10

How does the lamellipodia and filopodia move?

very dynamic forming and retracting rapidly

11

What is the molecular mechanism thought to be known for movement of cell?

1) cell pushes out front or leading edge
2)protrusions adhere to surface to form anchor
3)rest of cell uses anchorage point to pull cell forward
all steps involve actin and associated proteins

12

What does the initial steps of movement involve?

nucleating proteins - a type of ABP found at the plasma membrane promotes actin polymerization

13

When does integrins adhere to the surface?

when exploratory tip finds favorable environment

14

What are integrins?

transmembrane proteins that adhere to molecules in the extracellular matrix or on another cell

15

What do integrins also act with?

intracellular ABP
this gives the cell an anchor that spans from extracellular matrix to to the cytoplasmic cell cortex

16

What does actin filament severing proteins break?

some MF
changes cytoplasm from a thick, viscous gel-like solution into more aqueous solution as MF depolymerize
allows cytoplasm to flow more towards leading edge

17

why do myosin family proteins interact with other actin filaments?

to slide MFs in a given direction

18

What is internal contraction?

retract trailing edge
hydrolyze ATP

19

What is another responsibility of contractile actin?

forming belt around dividing cell
pinches two daughter cells apart during cell division

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