Alveolar macrophages are also involved in the phagocytosis of apoptotic and necrotic cells. Defects in apoptotic cell clearance is usually associated with impaired phagocytosis of macrophages. Generally, tissue-resident macrophages are involved in immune homeostasis and the uptake of apoptotic bodies. Caspases play the central role in the transduction of ER apoptotic signals. Akt1 is involved in cellular survival pathways, by inhibiting apoptotic processes. This activates the effectors that in turn cleave other proteins resulting in apoptotic initiation. Twist also protects cancer cells from apoptotic cell death. Increased appearance of apoptotic cells also stimulates inefficient clearance. The method cannot distinguish between necrotic and apoptotic cells. The clearance of early apoptotic cells is an important function in multicellular organisms. C1q is capable of binding directly to apoptotic cells. The dying cells shrink and condense into apoptotic bodies. This process usually occurs in late apoptotic cells. Analogous to the apoptosome, which activates apoptotic cascades, the inflammasome activates a pyroptotic inflammatory cascade. C1q is an important contributor to the clearance of apoptotic cells and debris.