TI  - Endogenous <prot>presenilin 1</prot> redistributes to the surface of lamellipodia upon
      adhesion of Jurkat cells to a collagen matrix.
PG  - 7932-7
AB  - Most familial early-onset Alzheimer's disease cases are caused by
      mutations in the <prot>presenilin 1</prot> (<prot>PS1</prot>) gene. Subcellular localization of the
      endogenous <prot>PS1</prot> is essential for understanding its function, interactions
      with proteins, and role in Alzheimer's disease. Although numerous studies
      revealed predominant localization of <prot>PS1</prot> to endoplasmic reticulum and
      Golgi, there are conflicting reports on the localization of <prot>PS1</prot> to the
      cell surface. We found that endogenous <prot>PS1</prot> is highly expressed in T
      lymphocytes (Jurkat cells). Using a variety of methods, we present
      evidence that endogenous <prot>PS1</prot> is localized to the cell surface in addition
      to intracellular membrane compartments. Moreover, <prot>PS1</prot> appeared in high
      levels on the surface of lamellipodia upon adhesion of the cells to a
      collagen matrix. The redistribution of <prot>PS1</prot> in adhered cells was strikingly
      similar to that of the well characterized adhesion protein CD44. Cell
      surface  <prot>PS1</prot>  formed complexes in vivo with  actin-binding protein <prot>filamin</prot>
      (<prot>ABP-280</prot>) , which is known to form bridges between cell surface receptors
      and cytoskeleton and mediate cell adhesion and cell motility. Taken
      together, our results suggest a role of <prot>PS1</prot> in cell adhesion and/or
      cell-matrix interaction.
AD  - Department of Psychiatry and Behavioral Sciences, State University of New
