Possible signaling pathway for carbachol-induced pigment granule dispersion in bluegill RPE. In conjunction with previous evidence, a pathway that follows carbachol and forskolin (FSK) treatment is proposed. Arrows in red represent the pathway involved in dispersion; whereas, black arrows represent the aggregation pathway. All of the mediators shown have been tested with the exception of calmodulin, which may be required for calcineurin activation . The specific phosphorylated/dephosphorylated substrate(s) is(are) unknown. Abbreviations used are as follows (listed alphabetically): ATP, adenosine triphosphate; Ca2+i, intracellular free calcium ions; cAMPi, intracellular cyclic adenosine monophosphate; DAG, diacylglycerol; FSK, forskolin; Gαq, alpha subunit of the Gq family of GTP-binding proteins; IP3, inositol trisphosphate; Modd, muscarinic acetylcholine receptor subtype 1, 3, or 5; PIP2, phosphatidyl inositol bisphosphate;PKA, cAMP-dependent protein kinase;PLC, phospholipase C.
Johnson and García BMC Cell Biology 2007 8:53 doi:10.1186/1471-2121-8-53