Format

Send to

Choose Destination
Mol Microbiol. 2008 Feb;67(4):891-905. doi: 10.1111/j.1365-2958.2007.06102.x. Epub 2008 Jan 7.

Preferential localization of the endocytic internalization machinery to hyphal tips underlies polarization of the actin cytoskeleton in Aspergillus nidulans.

Author information

1
Departamento de Microbiología Molecular, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu, 9. Madrid 28040, Spain.

Abstract

AbpA, SlaB and AmpA, three demonstrated components of the endocytic internalization machinery, are strongly polarized in Aspergillus nidulans hyphae, forming a ring that embraces the hyphal tip, leaving an area of exclusion at the apex. AbpA, a prototypic endocytic internalization marker, localizes to highly motile and transient (average half life, 24 +/- 5 s) peripheral punctate structures overlapping with actin patches, which also predominate in the tip. SlaB also localizes to peripheral patches, but these are markedly more abundant and cortical than those of AbpA. In contrast to its polarized distribution in hyphae, endocytic patches show random distribution during the isotropic growth phase preceding polarity establishment, but polarize as soon as a germtube primordium emerges from the swelled conidiospore. Thus, while endocytosis can occur along the hyphae, the apical predominance and the spatial organization of actin patches and of the above endocytic machinery proteins as a slightly subapical ring strongly suggests that tight spatial coupling of apical secretion and subapical compensatory endocytosis underlies hyphal growth. In agreement, the phenotype of a null slaB allele indicates that endocytosis is essential.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Wiley
Loading ...
Support Center