Uncharacterized GTP-Binding Protein At5g64813 (AT5G64813) Arabidopsis Thaliana Recombinant Protein

The LIP1 gene encodes a small GTPase that influences the light input pathway of the plant circadian network. An MBP:LIP1 fusion protein has GTP hydrolyzing abilities in vitro. In plants, LIP1 seems to play a negative role in regulating circadian period that can be suppressed by light. LIP1 also seems to negatively affect light-pulse-dependent resetting of the clock, especially during the first portion of the subjective evening. LIP1 expression levels are not significantly affected by the circadian clock in seedlings grown under LL conditions. The levels of the YFP:LIP1 protein expressed under the control of the 35S promoter, shows a low amplitude variation, with protein levels peaking near the beginning of subjective night under LL conditions. In hypocotyl epidermal cells of dark and light-grown seedlings, a YFP:LIP1 fusion protein can be seen in the cytoplasm and the nucleus, and does not cluster in nuclear speckles. LIP1 may also be involved in photomorphogenesis.

Functional small GTPase that acts as a negative factor controlling the light-dependent period shortening of circadian rhythms and light-induced phase resetting during the subjective night (PubMed:17683937). May protect the clock from excessive or mistimed light (PubMed:17683937). Suppresses red and blue light-mediated photomorphogenesis and is required for light-controlled inhibition of endoreplication and tolerance to salt stress (PubMed:23144185). The entrainment of the circadian clock is independent from the other pleiotropic effects (PubMed:23144185). Could be a regulator of seedling establishment (PubMed:23144185).