Asynchronous maturation

Fig. 5 GPCR regulation of exocytosis downstream of Ca2+-entry. (a) Sequence of steps leading from recruitment to maturation of synaptic vesicles from a reserve pool (RP) to a readily-releasable pool (RRP) displaying slow (asynchronous) and fast (synchronous highly Ca2+-sensitive pool, HCSP synaptotagmin 1 (SYT 1) supported) components, (b) Protein-protein interactions of SNARES (SYX, syntaxin SYB, synaptobrevin and SNAP-2s-7S complex) and major putative regulatory proteins. Phosphoproteins are shown in shaded boxes (phosphorylation sites for PKA and PKC are indicated where known) with phosphorylation-dependent interactions depicted by arrows (increase indicated by filled arrows decrease indicated by open arrows). Circle-end connectors indicate a phosphorylation-independent or as yet unspecified interaction. Potential effects of interactions at various points of the sequence in A are discussed in the text.

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