Functional Analysis of Phosphatidylinositol Transfer Proteins Academic Article uri icon

abstract

  • The yeast phosphatidylinositol transfer protein (Secl4p) is required for Golgi secretory function. Our data indicate that the essential function of Sec!4p is to preserve the integrity of a Golgi diacylglycerol (DAG) pool that stimulates vesicle biogenesis from the Golgi complex. We suggest that the phosphatidylcholine-bound form of Secl4p acts to prevent Golgi DAG consumption, whereas the phosphatidylinositol-bound Secl4p functions in Golgi DAG production. Genetic data indicate that shunting of DAG to phosphatidic acid (PA) is detrimental to Secl4p-dependent yeast Golgi secretory activity; indicating that the stimulatory effects of DAG do not operate through generation of PA. The secretory distress associated with depletion of yeast Golgi DAG appears to be manifested through the action of Keslp, a polypeptide that shares primary sequence homology with the lipid binding domain of human oxysterol binding protein (OSBP). Identification of Keslp as a negative effector for Golgi function provides initial insight into the biological role of a member of the OSBP family, and describes a novel regulatory pathway that employs both a phosphatidylinositol transfer protein and a specific OSBP homolog in the regulation of Golgi-derived secretory vesicle biogenesis.

published proceedings

  • FASEB Journal

author list (cited authors)

  • Kearns, B. G., Alb, J. G., Cartee, R. T., & Bankaitis, V. A.

citation count

  • 1

complete list of authors

  • Kearns, Brian G||Alb, James G||Cartee, Robert T||Bankaitis, Vytas A

publication date

  • December 1996