Microtubule interaction of LICC1, a maize homologue of a component of the human muskelin/RanBPM/CTLH protein complex

Abstract

MRCTLH (muskelin/RanBPM/CTLH) is a protein complex found in humans (MRCTLH) that is involved in the regulation of numerous cellular processes, such as gluconeogenesis, cell signaling, development, nuclear extrusion, cell morphology, or stability of different proteins. According to genomic data, all eukaryotes have similar protein complexes. In yeast, a similar protein complex named GID was found to be involved in the regulation of gluconeogenesis. LICC1 is a maize protein whose sequence resembles that of TWA1 in humans and GID8 in yeast, which are central components of the MRCTLH and GID complexes. LICC1 contains three highly conserved protein domains, LisH, CTLH, and CRA, typical of this protein family. Twa1 and gid8 are unique genes in human and yeast genomes. However, three copies of licc1 are present in the maize genome and multiple copies are present in other plant genomes. This result suggests the presence of multiple variants of the MRCTLH/GID complex in plants, which could increase its regulatory capacity. We also demonstrate here that LICC1 has the ability to interact with microtubules, similarly to the human TWA1. This interaction reinforces the idea that the LICC1 protein from maize, and its homologues in plants and, in general, the GID/MRCTLH complex in plants, can perform biological functions similar to those in humans and yeast.