Figure 4.

Patterns of Ca²⁺ elevation in response to localized photorelease of caged Ins(1,4,5)P₃. (A) Photorelease of Ins(1,4,5)P₃ from a 10-μm diameter region at the rhizoid apex (E) caused Ca²⁺ elevation that propagated in a subapical direction but was generally (60% of cells, n = 23) restricted to the apical 40 μm. (B) Ins(1,4,5)P₃ release in the nuclear region induced a Ca²⁺ wave that propagated bidirectionally and did not permeate the nucleoplasm (8 out of 14 cells). (C) In a further six cells, Ca²⁺ release in the nuclear region gave an initial Ca²⁺ increase in the nucleoplasm followed by perinuclear Ca²⁺ waves. (D) Elemental Ca²⁺ elevations (>2 SD above the mean background) could be observed during propagation of Ins(1,4,5)P₃-induced Ca²⁺ waves in apical and subapical (not shown) regions. (E) Representative volume decrease in response to nuclear or apical Ins(1,4,5)P₃-induced Ca²⁺ elevations. The green area indicates volume decrease in a representative cell after release of caged Ins (1,4,5)P₃ in the apical rhizoid regions (n = 5). No volume decrease could be observed following Ins(1,4,5)P₃ release in nuclear regions. (Bar = 15 μm.)