6 Functions Of Proteins

attachment to the cytoskeleton

elements of the cytoskeleton (cells internal supports) and the extracellular matrix may be anchored to the membranes proteins, which help maintain cell shape and fix the location of the certain membrane proteins

cell-cell recognition

some glycoproteins (proteins bonded to short chains of sugar)

Receptors

A membrane protein exposed to the outside of the cell may be binding site with a specific shape that fits the shape of a chemical messenger, such as a hormone

Enzymatic Activity

A protein built into the membrane may be an enzyme with its active site exposed to substances in the adjacent solution. in some cases, several enzymes in a membrane act as a team.

Transport

A protein that spans the membrane may provide a hydrophilic channel across the membrane that is selective for a particular solute. (b) some transport proteins hydrolyze ATP as an energy source to actively pump substances across the membrane

intercellular joining

Membrane proteins of adjacent cells may be hooked together in various kinds of intercellular junctions.