The Secretory Pathway Mediates Localization of the Cell Polarity Regulator Aip3p/Bud6p

• DOI: 10.1091/mbc.11.2.647
• Publication Date: 2013-07-02T23:47:08Z
• Authors: Hui Jin; David C. Amberg
• Keywords: Cell polarity; Polarity (international relations)

Aip3p/Bud6p is a regulator of cell and cytoskeletal polarity inSaccharomyces cerevisiae that was previously identified as an actin-interacting protein. Actin-interacting protein 3 (Aip3p) localizes at the cortex where cytoskeleton assembly must be achieved to execute polarized growth, deletion ofAIP3 causes gross defects in polarity. We have discovered Aip3p localization mediated by secretory pathway. Mutations early- or late-acting components apparatus lead mislocalization. Biochemical data show pool associated with post-Golgi vesicles. An investigation sequences within necessary for has sequence N terminus sufficient directing localization. Replacement homologous region from aSchizosaccharomyces pombe allows normal localization, indicating pathway–mediated pathway conserved. Delivery also requires type V myosin motor Myo2p its regulatory light-chain calmodulin. These suggest one function calmodulin activate Myo2p's activity pathway; this likely movement late vesicles on actin cables.