What are the types of cell surface receptors?

There are three main types of cell-surface receptors: ion channel receptors, GPCRs, and enzyme-linked receptors

• Ion channel-linked receptors – Ion channel-linked receptors bind a ligand, opening a channel through the membrane that facilitates the passage of ions such as Na+, K+, Ca2+, and Cl− across the plasma membrane. These receptors play a vital role in triggering cellular response to toxins and venoms. They also mediate various biological processes involving rapid changes in cells such as the contraction of skeletal, cardiac and smooth muscles. Ion channel-linked receptors are also known as ionotropic receptors. 
• G-protein linked receptors – G-protein-coupled receptors (GPCRs) is the largest family of cell surface receptors and are made up of seven transmembrane proteins that are structurally and functionally related. GPCRs function as an intermediate transducer molecule. They play a vital role in activating the GTP binding proteins (trimeric membrane-bound G-proteins), which in turn stimulate either an enzyme or an ion channel (effector) in the cell membrane.  
• Enzyme-linked receptors – Enzyme-linked receptors are single-pass transmembrane proteins that may behave as enzymes or are linked to enzymes. They are also known as catalytic receptors. These types of receptors have an extracellular binding site for chemical signaling. They also have an intracellular domain whose catalytic action is regulated by the binding of an extracellular ligand. Irregularities in signaling via enzyme-linked receptors play a key role in disorders related to cell growth, proliferation, migration, survival, and differentiation, all of which are associated with the development of cancer. There are 6 types of enzyme-linked receptors.