<unk> s are a class of type-1 transmembrane proteins.  They play important roles in cell adhesion, ensuring that cells within tissues are bound together.  They are dependent on calcium (Ca2+) ions to function, hence their name.
The<unk>  superfamily includes<unk> s, protocadherins, desmogleins, and desmocollins, and more. In structure, they share<unk>  repeats, which are the extracellular Ca2+-binding domains. There are multiple classes of<unk>  molecule, each designated with a one-letter prefix (generally noting the type of tissue with which it is associated).<unk> s within one class will bind only to themselves. For example, an N-cadherin will bind only to another N-cadherin molecule. Because of this specificity, groups of cells that express the same type of<unk>  molecule tend to cluster together during development, whereas cells expressing different types of<unk>  molecules tend to separate.
Cadherin
Integrin
Collectin
Glutelin
Disintegrin
Lncap
Frizzled
Cell adhesion molecule