Structural highlights
Function
C1QL3_MOUSE May regulate the number of excitatory synapses that are formed on hippocampus neurons. Has no effect on inhibitory synapses. Plays a role in glucose homeostasis. Via AMPK signaling pathway, stimulates glucose uptake in adipocytes, myotubes and hepatocytes and enhances insulin-stimulated glucose uptake. In a hepatoma cell line, reduces the expression of gluconeogenic enzymes G6PC and PCK1 and hence decreases de novo glucose production.[1] [2]
Publication Abstract from PubMed
C1q-like (C1QL) -1, -2, and -3 proteins are encoded by homologous genes that are highly expressed in brain. C1QLs bind to brain-specific angiogenesis inhibitor 3 (BAI3), an adhesion-type G-protein coupled receptor that may regulate dendritic morphology by organizing actin filaments. To begin to understand the function of C1QLs, we determined high-resolution crystal structures of the globular C1q-domains of C1QL1, C1QL2, and C1QL3. Each structure is a trimer, with each protomer forming a jelly-roll fold consisting of 10 beta strands. Moreover, C1QL trimers may assemble into higher-order oligomers similar to adiponectin and contain four Ca(2+)-binding sites along the trimeric symmetry axis, as well as additional surface Ca(2+)-binding sites. Mutation of Ca(2+)-coordinating residues along the trimeric symmetry axis lowered the Ca(2+)-binding affinity and protein stability. Our results reveal unique structural features of C1QLs among C1q/TNF superfamily proteins that may be associated with their specific brain functions.
Structures of C1q-like Proteins Reveal Unique Features among the C1q/TNF Superfamily.,Ressl S, Vu BK, Vivona S, Martinelli DC, Sudhof TC, Brunger AT Structure. 2015 Apr 7;23(4):688-99. doi: 10.1016/j.str.2015.01.019. Epub 2015 Mar, 5. PMID:25752542[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Bolliger MF, Martinelli DC, Sudhof TC. The cell-adhesion G protein-coupled receptor BAI3 is a high-affinity receptor for C1q-like proteins. Proc Natl Acad Sci U S A. 2011 Feb 8;108(6):2534-9. doi: 10.1073/pnas.1019577108., Epub 2011 Jan 24. PMID:21262840 doi:http://dx.doi.org/10.1073/pnas.1019577108
- ↑ Wei Z, Peterson JM, Wong GW. Metabolic regulation by C1q/TNF-related protein-13 (CTRP13): activation OF AMP-activated protein kinase and suppression of fatty acid-induced JNK signaling. J Biol Chem. 2011 May 6;286(18):15652-65. doi: 10.1074/jbc.M110.201087. Epub 2011, Mar 4. PMID:21378161 doi:http://dx.doi.org/10.1074/jbc.M110.201087
- ↑ Ressl S, Vu BK, Vivona S, Martinelli DC, Sudhof TC, Brunger AT. Structures of C1q-like Proteins Reveal Unique Features among the C1q/TNF Superfamily. Structure. 2015 Apr 7;23(4):688-99. doi: 10.1016/j.str.2015.01.019. Epub 2015 Mar, 5. PMID:25752542 doi:http://dx.doi.org/10.1016/j.str.2015.01.019
