How do protein signal molecules differ from steroid signal molecules

Thanks.-Protein signaling molecules act most typically by changing the activity of another protein, usually through an enzymatic modification of the specific target. Protein kinases are a good example of a protein signaling molecule. Signaling cascades can begin at the cell membrane and transmit through numerous signaling molecules within the cell until thltimately impact on the pathway target.Steroid signaling molecules can typcally pass freely through cell membranes and are often able to transit directly to the nucleus of a cell where they are able to influence transcription or gene activation.......