Down Effects on the Processing of Nonconscious Masked Stimuli Top - Down

conductance by performing patch-clamp studies on fused giant synaptic vesicles. Such studies would also facilitate characterization of the mechanism through which TRPM7 may be activated in the membrane of synaptic vesicles. TRPM7 is a ‘‘chanzyme’’ consisting of fused channel and protein kinase domains (Nadler et al., 2001; Runnels et al., 2001), and while the authors showed that the channel activity is clearly required for neurotransmitter release, we do not know if the protein kinase contributes to TRPM7 function in synaptic vesicles. Despite questions concerning the exact mechanism through which TRPM7 regulates release of acetylcholine, the current study provides the first demonstration of a role for a Group 1 TRP in an intracellular membrane, as opposed to the plasma membrane. The Group 1 TRPs include TRPs that fall into the five subfamilies (TRPC, TRPV, TRPM, TRPA, and TRPN) that are most related to the original member of the superfamily, Drosophila TRP. Members of the distantly related Group 2 TRPs, such as TRPP2 and TRPML1, are known to be present primarily in intracellular compartments, although their precise functions remain elusive. The concept that such TRP channels are waiting in a dormant state to undergo regulated translocation to the plasma membrane almost certainly applies in some cases. Nevertheless, given the findings by Krapivinsky et al., it may turn out that many TRP channels, which are currently considered cation influx channels, have equally important roles in a variety of secretory vesicles and intracellular organelles.