6WSK

Crystal Structure of the Cannabinoid Receptor 1 Interacting Protein 1a (CRIP1a)

Summary for 6WSK

• Entry DOI: 10.2210/pdb6wsk/pdb
• Descriptor: Endolysin,CB1 cannabinoid receptor-interacting protein 1 fusion (2 entities in total)
• Functional Keywords: beta barrel, cargo carrier, signaling protein
• Biological source: Enterobacteria phage T4; More
• Total number of polymer chains: 1
• Total formula weight: 39214.86

Authors

Booth, W.T.,Howlett, A.C.,Lowther, W.T. (deposition date: 2020-05-01, release date: 2021-09-08, Last modification date: 2023-10-18)

Primary citation

Booth, W.T.,Clodfelter, J.E.,Leone-Kabler, S.,Hughes, E.K.,Eldeeb, K.,Howlett, A.C.,Lowther, W.T.
Cannabinoid receptor interacting protein 1a interacts with myristoylated G alpha i N terminus via a unique gapped beta-barrel structure.
J.Biol.Chem., 297:101099-101099, 2021

PubMed Abstract: Cannabinoid receptor interacting protein 1a (CRIP1a) modulates CB cannabinoid receptor G-protein coupling in part by altering the selectivity for Gα subtype activation, but the molecular basis for this function of CRIP1a is not known. We report herein the first structure of CRIP1a at a resolution of 1.55 Å. CRIP1a exhibits a 10-stranded and antiparallel β-barrel with an interior comprised of conserved hydrophobic residues and loops at the bottom and a short helical cap at the top to exclude solvent. The β-barrel has a gap between strands β8 and β10, which deviates from β-sandwich fatty acid-binding proteins that carry endocannabinoid compounds and the Rho-guanine nucleotide dissociation inhibitor predicted by computational threading algorithms. The structural homology search program DALI identified CRIP1a as homologous to a family of lipidated-protein carriers that includes phosphodiesterase 6 delta subunit and Unc119. Comparison with these proteins suggests that CRIP1a may carry two possible types of cargo: either (i) like phosphodiesterase 6 delta subunit, cargo with a farnesyl moiety that enters from the top of the β-barrel to occupy the hydrophobic interior or (ii) like Unc119, cargo with a palmitoyl or a myristoyl moiety that enters from the side where the missing β-strand creates an opening to the hydrophobic pocket. Fluorescence polarization analysis demonstrated CRIP1a binding of an N-terminally myristoylated 9-mer peptide mimicking the Gα N terminus. However, CRIP1a could not bind the nonmyristolyated Gα peptide or cargo of homologs. Thus, binding of CRIP1a to Gαi proteins represents a novel mechanism to regulate cell signaling initiated by the CB receptor.

PubMed: 34418434
DOI: 10.1016/j.jbc.2021.101099

Experimental method

X-RAY DIFFRACTION (1.55 Å)