Abstract
Early ultrastructural observations of Cryptosporidium parvum-infected cells consistentlydescribed the accumulation of microfilaments beneath the dense band, suggesting theinitiation of actin reorganization within the host cell. Immunolocalization and forcedexpression of β-actin green fluorescent protein confirmed the rearrangement of hostactin filaments, and recruitment of actin-binding proteins to infection sites. Subsequentstudies have demonstrated the importance of host signalling cascades leading to actinreorganization during early invasion events. Therefore, this chapter focuses on actin reorganizationduring sporozoite internalization and development, concentrating primarilyon the molecular mechanisms of actin reorganization.