The PICALM Signaling Antibody Sampler Kit provides an economical means of investigating PICALM signaling by western blot and labeling endo-lysosomal components by immunofluorescence (IF). This kit includes enough primary antibodies to perform two western blot experiments or at least 40 IF tests per primary antibody.

The antibodies in this kit serve to characterize phosphatidylinositol-binding clathrin assembly protein (PICALM)-mediated lysosomal maturation, as endo-lysosomal systems are important for normal physiology and prevention of common late-onset neurodegenerative diseases such as Alzheimer's disease (AD).

PICALM is a clathrin-binding protein involved in the endo-lysosomal pathway, where it has been genetically associated with AD (1,2). Clathrin is a triskelion-shaped protein that plays a major role in the formation of coated vesicles (1). Formation of these vesicles is critical for shaping the cell membrane to promote intracellular trafficking for multiple membrane trafficking pathways in the cell, including the trans-Golgi network as well as transport to and from the cell membrane and endosomal compartments. PICALM disruption increases the number of early endosomes, which is linked to exacerbated tau aggregation (2).  Early endosome antigen 1 (EEA1) is an early endosomal marker and a Rab5 effector protein essential for early endosomal membrane fusion and trafficking (3,4). Lysosome-associated membrane protein 1 (LAMP1) is an abundant lysosomal membrane protein involved in regulating lysosomal motility during lysosome-phagosome fusion (5,6). Cathepsin D (CSTD) is a ubiquitously expressed lysosomal aspartyl protease involved in the normal degradation of proteins (7). Mutations in PICALM were shown to cause lysosomal enzymes and membrane proteins to be mis-trafficked and accumulated; for example, immature forms of CTSD accumulate abnormally within endosomes. These changes correlate with reduced turnover of lysosomal cargoes generated by autophagy and endocytosis (2).