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):

This domain is found in the yeast cell wall assembly regulator Smi1 (also known as Knr4) [ (PUBMED:7937796) (PUBMED:8289782) ].

Saccharomyces cerevisiae Knr4 has a regulatory role in chitin deposition and in cell wall assembly [ (PUBMED:10206705) ]. It 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) ]. Knr4 also interacts with the tyrosine-tRNA synthetase protein encoded by Tys1 and is involved in sporulation process [ (PUBMED:11410349) ].

Proteins containing this domain also include the animal F-box only protein 3 (FBXO3). In humans, FBXO3 is a substrate recognition component of the SCF (SKP1-CUL1-F-box protein)-type E3 ubiquitin ligase complex [ (PUBMED:18809579) ].

Interestingly, Smi1/Knr4 homologues from bacteria are potential immunity proteins in a subset of these contact-dependent inhibitory toxin systems [ (PUBMED:21306995) ].

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 15672 SMI1_KNR4 domains in 15452 proteins in SMART's nrdb database.

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