부산대학교 도서관

Using affinity chromatography we identified the Aspergillus nidulans F-BAR-and-PH domain-containing protein BapH as a RabERAB11 effector. BapH localizes to the Spitzenkörper (SPK) in an F-actin- and Sec7-dependent manner, becoming cytosolic after inactivation of Trs120 in TRAPPII, the oligomeric GEF for RabERAB11. Therefore, RabERAB11 contributes to the recruitment of BapH to secretory vesicles in vivo. BapH has a close homologue, SlmA, which is related to yeast Slm1p/Slm2p, localizes to eisosomes and does not bind RabERAB11. bapHΔ, slmAΔ and double bapHΔ slmAΔ mutations do not affect growth, although slmAΔ results in myriocin hypersensitivity. Both the PH and the F-BAR domain in BapH are necessary to recruit the protein to membranes, whereas its C-terminal moiety negatively regulates localization to the SPK. Strong overexpression of full-length BapH or of BapH lacking the C-terminal moiety impairs growth. The tandemly duplicated PHBapH domain is recruited to the plasma membrane in a manner dependent on critical Lys residues in its 'noncanonical' lipid binding pocket, suggesting that it binds to biological membranes containing PtdIns(4,5)P2. Ablation of BapH, or deletion of the PH or BAR domains critical for the SPK localization increases autophagy under nitrogen-replete conditions. Therefore, BapH localizing to SPK vesicles influences basal levels of autophagy. [ABSTRACT FROM AUTHOR]