Calmodulin-binding protein essential for pollen germination, but not necessary for microsporogenesis or gametogenesis (PubMed:12928497). Interacts with calmodulin in a calcium-dependent manner. Expressed only in pollen and in pollen tubes. The calmodulin-binding domain (CBD) is located between A-448 and A-496. Normal pollen development, but no pollen germination.