SMI1_KNR4

SMI1 / KNR4 family
SMI1_KNR4
SMART accession number:SM00860
Description: Proteins in this family are involved in the regulation of 1,3-beta-glucan synthase activity and cell-wall formation.
Interpro abstract (IPR018958):

Proteins in this family are involved in the regulation of 1,3-beta-glucan synthase activity and cell-wall formation [(PUBMED:7937796), (PUBMED:8289782)].

Yeast members of this family are involved in the regulation of cell wall assembly. Saccharomyces cerevisiae (Baker's yeast) protein KNR4 (SMI1) has a regulatory role in chitin deposition and in cell wall assembly [(PUBMED:10206705)]. It was originally identified as a regulator of chitin synthase expression (acting as a repressor) [(PUBMED:10206705)] and of 1,3-beta-glucan synthase levels [(PUBMED:8289782)]. It was shown to localise in patches at presumptive bud sites in unbudded cells and at the incipient bud site during bud emergence [(PUBMED:10206705)].

KNR4 is believed to connect the PKC1-SLT2 MAPK pathway with cell proliferation. It has been shown to interact with BCK2, a gene involved in cell cycle progression in S. cerevisiae (forming a complex) to allow PKC1 to coordinate the cell cycle (cell proliferation) with cell wall integrity [(PUBMED:12185498), (PUBMED:12823808)]. PKC1 plays an essential role in cell wall integrity and cell proliferation through a bifurcated PKC1/mitogen-activated protein (MAP) kinase pathway. KNR4 also interacts with the tyrosine-tRNA synthetase protein encoded by TYS1 and is involved in sporulation process [(PUBMED:11410349)].

Note: previously reported evidence that KNR4 may interact with nuclear matrix-association region [(PUBMED:8516310)] may be due to an artefact [(PUBMED:10206705)].

Family alignment:
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There are 1157 SMI1_KNR4 domains in 1141 proteins in SMART's nrdb database.

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