btn1 affects endocytosis, polarization of sterol-rich membrane domains and polarized growth in Schizosaccharomyces pombe.
btn1, the Schizosaccharomyces pombe orthologue of the human Batten disease gene CLN3, exerts multiple cellular effects. As well as a role in vacuole pH homoeostasis, we now show that Btn1p is essential for growth at high temperatures. Its absence results in progressive defects at 37 degrees C that culminate in total depolarized growth and cell lysis. These defects are preceded by a progressive failure to correctly polarize sterol-rich domains after cytokinesis and are accompanied by loss of Myo1p localization. Furthermore, we found that in Sz. pombe, sterol spreading is linked to defective formation/polarization of F-actin patches and disruption of endocytosis and that these processes are aberrant in btn1Delta cells. Consistent with a role for Btn1p in polarized growth, Btn1p has an altered location at 37 degrees C and is retained in actin-dependent endomembrane structures near the cell poles or septum.
Codlin
Sandra
S
MRC Laboratory for Molecular Cell Biology, University College London, WC1E 6BT London, UK.
Haines
Rebecca L
RL
Mole
Sara E
SE
D000199:Actins / Q000378:metabolism; D004705:Endocytosis / Q000235:genetics* / Q000502:physiology; D005456:Fluorescent Dyes / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D021962:Membrane Microdomains / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011726:Pyridinium Compounds / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics* / Q000254:growth & development*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism*; D013261:Sterols / Q000737:chemistry; D013696:Temperature
D000199:Actins; C509077:BTN1 protein, S pombe; C092350:FM 4-64; D005456:Fluorescent Dyes; D008565:Membrane Proteins; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D029702:Schizosaccharomyces pombe Proteins; D013261:Sterols; D049452:Green Fluorescent Proteins