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The yeast ubiquitin‐like domain protein Mdy2 is required for microtubule‐directed nuclear migration and localizes to cytoplasmic granules in response to heat stress
Author(s) -
Cohnen André,
Bielig Harald,
Hollenberg Cornelis P.,
Hu Zheng,
RamezaniRad Massoud
Publication year - 2010
Publication title -
cytoskeleton
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 86
eISSN - 1949-3592
pISSN - 1949-3584
DOI - 10.1002/cm.20477
Subject(s) - biology , microbiology and biotechnology , nuclear transport , nuclear localization sequence , mitosis , cytoplasm , stress granule , microtubule , spindle pole body , nuclear protein , cell nucleus , saccharomyces cerevisiae , nuclear pore , spindle apparatus , cell division , biochemistry , yeast , translation (biology) , cell , transcription factor , gene , messenger rna
Abstract MDY2 encodes a ubiquitin‐like (UBL)‐domain protein necessary for efficient mating in Saccharomyces cerevisiae . Unlike most UBL proteins, Mdy2 is apparently not subject to C‐terminal processing and is localized predominantly in the nucleus. Deletion of MDY2 is associated with a five‐ to seven‐fold reduction in mating efficiency, mainly due to defects in nuclear migration and karyogamy at the prezygotic stage. Here, we looked for two potential interacting partners of Mdy2, investigated the function of Mdy2 in nuclear movement, determined the increased heat sensitivity defects of mdy2 Δ mutants, and inspected localization of Mdy2. Coprecipitation studies show that Mdy2 associates with α‐tubulin and with the microtubule (MT)‐associated dynactin subunit p150 Glued /Nip100. nip100 Δ mutants exhibit no defects in nuclear migration or in MT length or orientation during shmooing growth. Deletion of MDY2 display small nuclear migration phenotype during vegetative growth and seems to exacerbate the defects in mitotic nuclear migration seen in the nip100 Δ strain. Deletion of MDY2 increased heat sensitivity of the cells and these strains accumulate mitotic nuclear migration defects and shortened MTs under these conditions. GFP‐Mdy2 proteins which are localized predominantly in the nucleus at permissive temperature are localized to cytoplasmic foci during heat shock. Colocalization studies revealed that heat stress‐induced enrichment of Mdy2 in cytoplasmic foci merged mainly with stress granules marker Pab1. During glucose deprivation a minority of Mdy2 foci overlapped with P‐bodies marker Dcp2, while most Mdy2 foci and Pab1 foci overlap. Accordingly, we propose that Mdy2 plays a critical role in the MT‐dependent processes of karyogamy and stress response. © 2010 Wiley‐Liss, Inc.