G proteins are so-called because they bind the guanine nucleotides GDP and GTP. They are heterotrimers (i.e., made of three different subunits) associated with. the inner surface of the plasma membrane and. transmembrane receptors of hormones, etc. These are called G protein-coupled receptors (GPCRs).
Apply the metal paint to the mailbox in slow and even sections. Be sure to cover every inch of the metal mailbox including the door, hanging lip and the back. When this layer is dry remove the tape from the mailbox flag.
Cast iron can be painted with an oil-based metal primer and paint. If the iron is rusty or has been previously painted, the rust or paint should be removed before new painting is begun. Oil-based painting can be messy and the paint can take several hours to dry. Spray-paint can also be applied to cast iron.