A possible role of myristoylated alanine-rich C kinase substrate in endocytic pathway of Alzheimer's disease

It is believed that amyloid-beta peptide (A beta) plays a central role in the pathogenesis of Alzheimer's disease (AD). Thus, the process of amyloid precursor protein (APP) cleavage is a key event and has raised much attention in the field of AD research. It is proposed that APP, beta-and gamma-secretases are all located on the lipid raft, and the meeting of them is an indispensable step for A beta generation. Endocytosis can lead to clustering of APP, beta-and gamma-secretases from separate smaller lipid rafts into a larger one. On the other hand, for myristoylated alanine-rich C kinase substrate (MARCKS), phosphorylation by protein kinase C (PKC) or interaction with Ca2+ can lead to its release from membrane into cytoplasm. This process induces the release of actins and phosphatidylinositol 4, 5-bisphosphate (PIP2), which are important factors for endocytosis. Thus, the present review proposes that MARCKS may be implicated in A beta generation, by modulating free PIP2 level and actin movement, causing endocytosis.