Cell Bio Exam 3 - Cell Adhesions, Cell Junctions, and Extracellular Matrix

Multicellular organisms relay on ____________ that link cells. Organizes cells into __________

Macromolecules, tissues

Molecules engaged in adhesion

Adhesion receptors

Cells in tissues adhere to one another through specialized membrane proteins (CAMs) (also called receptors)

Cell-adhesion molecules

Cells adhere indirectly through binding of _____-_______ adhesion receptors to components of the extracellular matrix

cell-matrix

Most adhesion proteins are _______________ proteins

transmembrane

Allows cells to attach, but also allow connections to be dynamically altered

Molecular velcro

Immunoglobin superfamily, Cadherins, Lectins, and Integrins are all types of _____________ proteins

Adhesion

______________ adhesion is between cells of the same type

Homotypic

_____________ Binding is interactions with identical molecules

Homophilic

Use of antibodies that bind to cell adhesion molecules lead to the discovery of

cadherins

Downregulation of __________ allows cancer cells to undergo epithelial-to-mesenchymal transition (EMT), where cells lose _________ properties and acquire ________

E-Cadherin, adhesive, motility

Development of secondary malignant growths to a secondary site

Metastasis

Cell-Cell contact inhibits cell proliferation and motility

Contact inhibition

EC1-EC2 Cis interaction are defined by binding of the EC1 domain of one cadherin to the EC2 domain of an adjacent cadherin on the _________ cell

same

EC1-EC1 trans interaction are defined by binding of EC1 domain of one cadherin to the EC1 domain of a cadherin on the ___________ cell

adjacent

(1) At rest, Leukocytes and endothelial cells _________ interact

do not

(2) In response to inflammation vesicle-sequestered selectins move to the cell surface of endothelial cells mediating weak binding of leukocytes through interactions with ____________ ligand

carbohydrate

__________ are present on both the leukocyte and endothelial cell

Selectins

(3) Activation of endothelial cells lead to expression and secretion of _____________ (PAF) which induces a shape change and __________ leukocyte ____________

platelet, activates, integrins

(4) Binding of activated integrins on the leukocyte and CAMs on the endothelium (ICAM) results in _____ ___________

firm adhesion

(5) Firm adhesion leads to subsequent movement (_____________) into the underlying tissue

Extravasation

___________ junctions are used to form tissues and organs

cell-cell

The three major types of cell junctions are

Anchoring, tight, gap

______________ Junctions link adjoining cells to each other, which enables cells to function as a unit

Adhesive

The two main kinds of adhesive junctions are ____________ and ______________

Adherens, desmosomes

___________ (Cadherins, zipper) are a continuous belt near the apical region of the cell, initiate and stabilize cell adhesion, prominent in epithelial cells, and bind to actin microfilaments

Adherens

____________ are button like points of strong adhesion, enables cells to resist stress, prominent in skin, heart muscle, and uterus, and bind to intermediate filaments

Desmosomes

Adhesive junctions all have two kinds of proteins ________________ (inside membrane) and ____________ (outside membrane)

Intracellular attachment proteins, cadherins

__________ junctions prevent the movement of molecules across cell layers.

Tight

Epithelial tissues form barriers between _______ cells and the _________ environment (intestinal cells)

internal, outside

Tight junctions are abundant in intestinal epithelial cells, ________, __________ and the ____________

Liver, pancreas, bladder

The two types of CAMs are

Occulin, Claudin

________ junctions allow electrical and chemical communication between cells

Gap

Gap junctions create small gap between cells, spanned by small “_____________”, point of cytoplasmic contact through which ______ and ________ molecules can pass. Prominent in muscles and nerves

pipelines, ions, small

Gap junctions are composed of _____________, which facilitate rapid transmission of cell signals

connexins

The ____ participles in adhesion, signaling, and other functions

ECM

The extracellular matrix is primarily comprised of ________ proteins like collagens, protein-________ complexes like proteoglycans, and _________ glycoproteins like multi-adhesive matrix proteins

structural, polysaccaride, adhesive

The ECM functions in Anchoring, biomechanics properties, controlling cellular polarity, inhibiting or facilitating cell migration, and activating cell surface signaling receptors (x)

x

Fibers that provide structural integrity, mechanical strength, and resilience

Collagens

Most organized groups of cells are surrounded by the __________, a sheet-like meshwork of ECM

basal lamina

Collagen triple helix, forms due to unusual abundance of 3 amino acids:

Glycine, proline, hydroxyproline

Collagens have ____ globular domains, with the smaller one being at the __-term and the larger one being at the __-term

2, N, C

Collagenous triple helix is interrupted by ________ segments introducing flexibility

nonhelical

_______________ is the principle multi-adhesive matrix protein. At least 16 different forms. Large, cross shaped proteins. 5 globular domains

Laminin

_______________ is the major secreted proteoglycan. Consists of a large multi domain core proteins to which polysaccharides are covalently attached. 5 distinct domains. Globular repeats make it look like a long string of pearls

Perlecan

The 3 covalently attached polysaccharide chains that make up perlecan are ____-linked chains, ____-linked chains, and glycosaminoglycans (GAGs)

N, O

Proteoglycan complexes are called proteoglycan _____________

aggregates

The _____________ is comprised of layers of ECM components such as Type IV collagen, laminin, perlecan, and nidogen

Basal lamina

Cell-ECM Signaling involves

1. Binding of _______ to their ligands induces a conformational change, interacts with adapter proteins

2. Protein __________- transmit these signals via diverse signaling pathways

3. Regulates numerous cellular responses

Integrins, kinases

Intracellular adapter proteins can also modify the ability of _________ to bind their extracellular ligands

integrins