Cadherins vs Integrins vs Selectins

Cell Adhesion Molecules: Cadherins, Integrins and Selectins Compared

By StudyStore · Published 2026-11-04 · 1 min read · 229 words

Cell adhesion molecules (CAMs) are membrane proteins that attach a cell to neighbors or to the extracellular matrix. The MCAT usually tests which family does which job.

Comparison

Family	Binds	Ca²⁺ needed	Main role
Cadherins	Other cadherins (cell to cell, like to like)	Yes	Strong cell-cell adhesion, adherens junctions and desmosomes
Integrins	Extracellular matrix (collagen, fibronectin, laminin)	Requires divalent cations	Cell-matrix attachment and signaling to the cytoskeleton
Selectins	Carbohydrates on other cells	Yes	Brief leukocyte rolling on endothelium during inflammation
IgSF CAMs (NCAM, ICAM)	Other IgSF CAMs or integrins	No	Neural adhesion; ICAM supports firm leukocyte adhesion

Leukocyte recruitment

Selectins let a white blood cell roll along the vessel wall.
Chemical signals activate integrins on the leukocyte.
Integrins bind ICAMs on the endothelium for firm adhesion.
The cell squeezes between endothelial cells into tissue.

Cell junctions recap

Tight junctions: seal the space between cells (claudins, occludin).
Desmosomes: spot welds anchored to intermediate filaments, built from cadherins.
Gap junctions: channels that join cytoplasms (connexons).
Hemidesmosomes: link cells to the basement membrane via integrins.

Common traps

Mixing up cadherins and integrins. Cadherins join cells to cells; integrins join cells to matrix.
Forgetting that cadherins need calcium.
Assuming selectin binding is strong. It is transient and enables rolling.

One-minute recap

Cadherin: cell-cell, calcium dependent.
Integrin: cell-matrix.
Selectin: carbohydrate binding, rolling.

Check yourself: 5-question mini-quiz

Try each question first, then click it to reveal the answer.

1. What do cadherins bind?

Other cadherins on neighboring cells.

2. What do integrins bind?

Components of the extracellular matrix, such as collagen and fibronectin.

3. Which adhesion molecules bind carbohydrates?

Selectins.

4. What step do selectins mediate in leukocyte recruitment?

The initial rolling along the endothelium.

5. Which junction links a cell to the basement membrane using integrins?

The hemidesmosome.

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Written by StudyStore from standard scientific facts. Study aid only. Always check values against the reference your exam provides.