Devo Lect 8 + 9 - Cell connections Flashcards Preview

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Flashcards in Devo Lect 8 + 9 - Cell connections Deck (16):
2

Townes and Holtfreter experiment

separated cells with alkaline solution which spread out, placed in nutrients. Then they clumped together, moved about, then stop (stuck together)

3

Cell adhesion molecules

Used in epithelial sheets, serve to condense mesenchyme; eg L-selectin on blastocyst; cadherins

4

Cadherins

very common; homophilic (bind to same type); need Ca to bind; link to cytoskeleton (actin); usually cause contact inhibition. E (embryonic/ectodermal), P (placental), N (neural) types

5

Cadherin knockout mice

E knockouts: cannot implant; N knockout: nervous system doesn’t develop much, aborted

6

CAMs

Cell Adhesin Molecule; immunoglobulin-like domains, homophilic; N-CAM important in brain development; can work with cadherins; attraction or repulsion (low or high sialic acid - negative charge)

7

Substrate adhesion molecules

bind cells to ECM (basal lamina); fibronectin: glycoprotein binds to integrins, allows cells to bind to it and move along

8

Integrins

Bind fibronectin at RGD a.a. sequence, provide anchor; can also cause signal transduction as things bind to it

9

Cell junctional molecules

Gap junctions; form at morula stage and in early heart;

10

Cell adhesion in implantation

Blastocyst has L-selectin, E and P-cadherins so it can bind to endometrium wall; integrins on uterus and fibronectins on outside of blastocyst; serve to bind and signaling

11

Cell crawling

Protrusion of leading edge; form focal contacts; retraction of trailing edge

12

Cell motility components

contractile elements of cytoskeleton needed; lamellipodium: big front edge, more continuous; filopodia: small, spiky projections; focal contacts bind to substrates (ie. integrins); microfilaments (major) and microtubules

13

Microfilaments in cell motility

Major contributor; Constantly forming and breaking down; high concentration along the front edge; actin experiments (blocking it)

14

Haptotaxis

Guiding molecule is not freely diffusable, attached to something; ex: mesoderm cells follow fibronectin as they migrate inward

15

Galvanotaxis

Changes in voltage which can alter cellular movement, align themselves. Important in wound healing. Skin and nerve cells respond to this

16

Contact guidance

One cell moves and creates a path, another cell will follow

17

Contact inhibition

Movement is decreased after making contact with another. Most cells do this (not cancer cells)