Molecular basis of signalling in the spermatozoon.
The spermatozoon contains cell surface receptors for various egg-associated molecules, one of which has now been identified as the enzyme guanylate cyclase. A single membrane-spanning region divides the enzyme such that about one-half is extracellular and one-half is intracellular. A new paradigm for signal/transduction is established by these observations, in that a hormone or effector molecule binding to an extracellular site activates the catalytic domain of the same protein, resulting in the increased formation of a low molecular weight second messenger. Research on signalling mechanisms in the spermatozoon clearly apply to a diversity of cellular processes as well as to fertilization.
Garbers
D L
DL
Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-0295.
D000595:Amino Acid Sequence; D000818:Animals; D008297:Male; D008969:Molecular Sequence Data; D012617:Sea Urchins / Q000502:physiology; D015398:Signal Transduction; D013094:Spermatozoa / Q000502:physiology*