KEY RESOURCES TABLE

REAGENT or RESOURCE	SOURCE	IDENTIFIER
Antibodies
Mouse monoclonal anti-Kirrel3; clone N321C/49	Neuromab	Catalog no. 75–333; RRID: AB_2315857
Rabbit polyclonal anti-VGLUT2	Synaptic Systems	Catalog no. 135402; RRID: AB_2187539
Anti-FLAG M2 antibody	Sigma	Catalog no. F3165; RRID: AB_259529
THE™ His tag antibody [iFluor 488]	GenScript	Catalog no. A01800
Secondary donkey anti-mouse Alexa Fluor 488	Thermo Fisher	Catalog no. A-21202; RRID: AB_141607
Rat anti-HSC70/HSP73	Enzo Life Sciences	Catalog no. ADI-SPA-815-D; RRID: AB_2039279
Rabbit anti-β-actin	Cell Signaling Technology	Catalog no. 8457P; RRID: AB_10950489
Chemicals, peptides, and recombinant proteins
Anti-DYKDDDDK G1 affinity resin	GenScript	Catalog no. L00432
Rhodamine-Griffonia (Bandeiraea) Simplicifolia Lectin I	Vector Laboratories	Catalog no. RL-1102–2
EZ-link Sulfo-NHS-SS-Biotin	Thermo Fisher	Catalog no. 21331
Hoechst 33342	Thermo Fisher	Catalog no. H3570
Critical commercial assays
Super Signal Western Femto Kit	Thermo Fisher	Catalog no. 34094
Deposited data
Crystal structure and structure factors for mKirrel2 D1	This paper	PDB: 7LTW
Crystal structure and structure factors for mKirrel3 D1	This paper	PDB: 7LU6
Small-angle X-ray scattering data for mKirrel2 ECD	This paper	SASBDB: SASDMN2
Small-angle X-ray scattering data and model for mKirrel3 ECD	This paper	SASBDB: SASDMP2
Small-angle X-ray scattering data and model for mKirrel3 Q128A ECD	This paper	SASBDB: SASDMQ2
Experimental models: Cell lines
D. melanogaster S2 cells	Laboratory of K. Christopher Garcia	N/A
Trichoplusia ni High Five (BTI-TN-5B1–4) cells	Laboratory of K. Christopher Garcia	Thermo Fisher B85502
Experimental models: Organisms/strains
EC2-tau-lacZ mouse line (Tg(Vmn2r43-lacZ*)#Ddg)	Cloutier et al., 2004	N/A
Oligonucleotides
PCR genotyping WT5′- GATGATGCCGTGTATGAGTGCCAG	This paper	N/A
PCR genotyping WT3′- GAAATCCAAAGGTGAGCCTCC (common to WT and Q128A alleles)	This paper	N/A
PCR genotyping Q128A5′- GATGACGCCGTGTATGAGTGCGCC	This paper	N/A
Software and algorithms
HKL2000	Otwinowski and Minor, 1997	https://hkl-xray.com/
PHASER v. 2.6.0	McCoy et al., 2007	https://www.phaser.cimr.cam.ac.uk
PHENIX suite v. 1.19.1	Liebschner et al., 2019	http://phenix-online.org/
phenix.refine	Afonine et al., 2012	https://phenix-online.org/documentation/reference/refine_gui.html
Coot	Emsley et al., 2010	https://www2.mrc-lmb.cam.ac.uk/personal/pemsley/coot/
MUSCLE v. 3.8.425	Edgar, 2004	https://www.drive5.com/muscle/
RAxML-NG v. 1.0.1	Kozlov et al., 2019	https://github.com/amkozlov/raxml-ng
RAxML v. 8.2.12	Stamatakis, 2014	https://github.com/stamatak/standard-RAxML
MODELTEST-NG	Darriba et al., 2020	https://github.com/ddarriba/modeltest
PAML v. 4.8	Yang, 2007	http://abacus.gene.ucl.ac.uk/software/paml.html
SEDFIT	Schuck, 2000	http://www.analyticalultracentrifugation.com
SEDNTERP	Laue et al., 1992	http://www.jphilo.mailway.com/download.htm
SEDPHAT	Schuck, 2003	http://www.analyticalultracentrifugation.com
GUSSI	Brautigam, 2015.	https://www.utsouthwestern.edu/labs/mbr/software/
I-TASSER	Yang and Zhang, 2015	https://zhanglab.dcmb.med.umich.edu/I-TASSER/
BioXTAS RAW v. 2.0.2	Hopkins et al., 2017	https://bioxtas-raw.readthedocs.io/
GNOM v. 5.0 (r10552)	Svergun, 1992	https://www.embl-hamburg.de/biosaxs/gnom.html
ATSAS 3.0.2 (r12592)	Manalastas-Cantos et al., 2021	https://www.embl-hamburg.de/biosaxs/software.html
DAMMIF r12593	Franke and Svergun, 2009	https://www.embl-hamburg.de/biosaxs/dammif.html
EOM r12736	Tria et al., 2015	https://www.embl-hamburg.de/biosaxs/eom.html
SASREF (from ATSAS 3.0.2, r12592)	Petoukhov and Svergun, 2005	https://www.embl-hamburg.de/biosaxs/sasref.html
ASTRA v. 7.3.2.19	Wyatt Technology	https://www.wyatt.com/products/software/astra.html
Breaking-Cas	Oliveros et al., 2016	https://bioinfogp.cnb.csic.es/tools/breakingcas
Fiji	Schindelin et al., 2012	https://imagej.net/software/fiji/