What different kinds of proteins are there in a cell membrane?
The plasma membrane has *lots* of different kinds of proteins in (and on) it: – pumps (which actively move substances from one side to the other) – pores (which passively allow substances to flow through, but which will be able to be opened and closed controllably) – receptors (like growth factor receptors, which will detect a growth factor outside the cell, and propagate a signal across to the cytoplasm) – histocompatability proteins (which signal the tissue type of the cell and are important in “self” recognition) – adhesion proteins (which attach to extracellular proteins and stick the cell in place. They also allow migration by the cell using these as “anchors” by which to pull itself along) – signalling proteins (like enzymes which respond to a signal by modifying other proteins, or even the phospholipids of the membrane) the list goes on… And different membrane systems in the cell all have their own, different membrane proteins! Transmembrane proteins are integral membrane prot
