SPACA5B

Summary

SPACA5B (sperm acrosome associated 5B, HGNC:19142) is a protein-coding gene on chromosome Xp11.23, encoding Sperm acrosome-associated protein 5 (Q96QH8).

Predicted to enable lysozyme activity. Predicted to be involved in fusion of sperm to egg plasma membrane involved in single fertilization. Predicted to be located in extracellular region. Predicted to be active in acrosomal vesicle and sperm flagellum.

Source: NCBI Gene 729201 — RefSeq curated summary.

At a glance

• Clinical variants (ClinVar): 1 total
• MANE Select transcript: NM_001079900

Identifiers

Gene identifiers

Field	Value
HGNC ID	HGNC:19142
Approved symbol	SPACA5B
Name	sperm acrosome associated 5B
Location	Xp11.23
Locus type	gene with protein product
Status	Approved
Aliases	LYZL5B
Ensembl gene	ENSG00000171478
Ensembl biotype	protein_coding
Entrez	729201

Gene structure

Transcript identifiers

Ensembl transcripts: 1 — 1 protein_coding

ENST00000304270

RefSeq mRNA: 1 — MANE Select: NM_001079900 NM_001079900

CCDS: CCDS35238

Canonical transcript exons

ENST00000304270 — 4 exons

Exon	Start	End
ENSE00001472186	48130626	48130832
ENSE00001713723	48131261	48131419
ENSE00001733014	48132250	48132328
ENSE00001762700	48132433	48132620

Expression profiles

Bgee: expression breadth broad, 85 present calls, max score 87.42.

Top tissues by expression

123 total, by Bgee expression score (0-100, higher = more expressed):

Tissue	Anatomy ID	Expression score	Quality
male germ line stem cell (sensu Vertebrata) in testis	CL:0000089 ∩ UBERON:0000473	87.42	gold quality
left testis	UBERON:0004533	86.24	gold quality
testis	UBERON:0000473	85.36	gold quality
right testis	UBERON:0004534	85.23	gold quality
colonic epithelium	UBERON:0000397	50.29	silver quality
bone marrow cell	CL:0002092	47.98	gold quality
tonsil	UBERON:0002372	37.99	gold quality
bone marrow	UBERON:0002371	37.78	gold quality
metanephros cortex	UBERON:0010533	37.09	gold quality
ventricular zone	UBERON:0003053	36.48	gold quality
cortical plate	UBERON:0005343	36.47	gold quality
ganglionic eminence	UBERON:0004023	35.49	gold quality
skeletal muscle tissue	UBERON:0001134	35.21	gold quality
urinary bladder	UBERON:0001255	32.72	silver quality
muscle tissue	UBERON:0002385	32.40	gold quality
hindlimb stylopod muscle	UBERON:0004252	32.15	gold quality
right lung	UBERON:0002167	31.84	gold quality
blood	UBERON:0000178	31.33	gold quality
olfactory segment of nasal mucosa	UBERON:0005386	30.94	gold quality
sural nerve	UBERON:0015488	30.93	gold quality
prefrontal cortex	UBERON:0000451	30.34	gold quality
cortex of kidney	UBERON:0001225	30.05	silver quality
stromal cell of endometrium	CL:0002255	29.87	gold quality
lymph node	UBERON:0000029	29.77	gold quality
superior frontal gyrus	UBERON:0002661	29.30	gold quality
duodenum	UBERON:0002114	28.14	gold quality
islet of Langerhans	UBERON:0000006	28.08	gold quality
right ovary	UBERON:0002118	27.46	gold quality
vermiform appendix	UBERON:0001154	26.42	gold quality
pancreas	UBERON:0001264	26.16	gold quality

Single-cell (SCXA)

Detected in 1 experiment(s), a significant marker in 0.

Experiment	Marker?	Max mean expression
E-ANND-3	no	0.32

Regulation

Is transcription factor: no

Cross-species orthologs

14 orthologs

Organism	Symbol	Gene ID
mus_musculus	Spaca5	ENSMUSG00000037167
rattus_norvegicus	Spaca5	ENSRNOG00000045622
drosophila_melanogaster	LysB	FBGN0004425
drosophila_melanogaster	LysD	FBGN0004427
drosophila_melanogaster	LysE	FBGN0004428
drosophila_melanogaster	LysP	FBGN0004429
drosophila_melanogaster	LysS	FBGN0004430
drosophila_melanogaster	LysX	FBGN0004431
drosophila_melanogaster	CG16756	FBGN0029765
drosophila_melanogaster	CG7798	FBGN0034092
drosophila_melanogaster	CG16799	FBGN0034538
drosophila_melanogaster	CG11159	FBGN0034539
drosophila_melanogaster	CG8492	FBGN0035813
drosophila_melanogaster	CG30062	FBGN0050062

Paralogs (8): LYZ (ENSG00000090382), LYZL1 (ENSG00000120563), SPACA3 (ENSG00000141316), LYZL2 (ENSG00000151033), LYZL4 (ENSG00000157093), LALBA (ENSG00000167531), SPACA5 (ENSG00000171489), LYZL6 (ENSG00000275722)

Protein

Protein identifiers

Sperm acrosome-associated protein 5 — Q96QH8 (reviewed: Q96QH8)

Alternative names: Lysozyme-like protein 5, Sperm-specific lysozyme-like protein X

All UniProt accessions (2): A0A140VJN7, Q96QH8

UniProt curated annotations — full annotation on UniProt →

Subcellular location. Secreted.

Similarity. Belongs to the glycosyl hydrolase 22 family.

RefSeq proteins (1): NP_001073369* (*=MANE)

Domains & families (InterPro)

ID	Name	Type
IPR000974	Glyco_hydro_22_lys	Family
IPR001916	Glyco_hydro_22	Family
IPR023346	Lysozyme-like_dom_sf	Homologous_superfamily

Pfam: PF00062

UniProt features (9 total): disulfide bond 4, signal peptide 1, chain 1, domain 1, active site 1, sequence conflict 1

Structure

Experimental structures (PDB)

0 structures.

Predicted structure (AlphaFold)

Model	pLDDT	Fraction very-high
AF-Q96QH8-F1	91.04	0.80

Functional residue map

Curated UniProt residues grouped by drug-discovery relevance — catalytic, ligand-binding, modification, and mutation-validated positions. Source: UniProtKB sequence features.

Catalytic / active sites (1): 56

Disulfide bonds (4): 27–147, 51–135, 85–100, 96–114

Function

Pathways and Gene Ontology

Reactome pathways

0 pathways

MSigDB gene sets: 22 (showing top): GOBP_SINGLE_FERTILIZATION, GOCC_SECRETORY_GRANULE, GOBP_MEMBRANE_FUSION, GOBP_PLASMA_MEMBRANE_ORGANIZATION, GOBP_CELLULAR_PROCESS_INVOLVED_IN_REPRODUCTION_IN_MULTICELLULAR_ORGANISM, GOBP_ENDOMEMBRANE_SYSTEM_ORGANIZATION, GOBP_PLASMA_MEMBRANE_FUSION, GOBP_MEMBRANE_ORGANIZATION, GOBP_FERTILIZATION, GOCC_SECRETORY_VESICLE, GOCC_MOTILE_CILIUM, GOCC_ACROSOMAL_VESICLE, GOCC_CILIUM, GOMF_LYSOZYME_ACTIVITY, GOMF_HYDROLASE_ACTIVITY_ACTING_ON_GLYCOSYL_BONDS

GO Biological Process (1): fusion of sperm to egg plasma membrane involved in single fertilization (GO:0007342)

GO Molecular Function (3): lysozyme activity (GO:0003796), hydrolase activity (GO:0016787), hydrolase activity, acting on glycosyl bonds (GO:0016798)

GO Cellular Component (3): acrosomal vesicle (GO:0001669), extracellular region (GO:0005576), sperm flagellum (GO:0036126)

GO top-level categories

Rollup of top GO terms by namespace:

Category	Terms
single fertilization	1
cellular process involved in reproduction in multicellular organism	1
hydrolase activity, hydrolyzing O-glycosyl compounds	1
peptidoglycan muralytic activity	1
catalytic activity	1
hydrolase activity	1
secretory granule	1
cellular anatomical structure	1
9+2 motile cilium	1

Protein interactions and networks

STRING

378 interactions, top by confidence (×1000):

Protein A	Protein B	Partner UniProt	Score
SPACA5B	ZNF630	Q2M218	627
SPACA5B	ZNF212	Q9UDV6	472
SPACA5B	CYLC1	P35663	468
SPACA5B	TMEM190	Q8WZ59	452
SPACA5B	ZNF182	P17025	446
SPACA5B	ZNF81	P51508	418
SPACA5B	CIMAP1A	Q96PU9	380
SPACA5B	IZUMO4	Q1ZYL8	376
SPACA5B	AKAP14	Q86UN6	374
SPACA5B	TCP11	Q8WWU5	371
SPACA5B	C12orf71	A8MTZ7	363
SPACA5B	ODF4	Q2M2E3	362
SPACA5B	ASTL	Q6HA08	358
SPACA5B	EOLA1	Q8TE69	358
SPACA5B	IZUMO2	Q6UXV1	354

IntAct

0 interactions, top by confidence:

ESM2 similar proteins: A2AE20, C0HLB7, C1IIX1, D4ABW7, D9J142, D9J143, G3XDT7, O75951, P00702, P00709, P00710, P00711, P00712, P00713, P00714, P00716, P05105, P07458, P08334, P08896, P09462, P11375, P11376, P12065, P18137, P28546, P29752, P30805, P37161, P48816, P50717, P50718, P51782, P61944, P81646, P81708, P85045, Q06655, Q29145, Q29RT1

Diamond homologs: A0JNM6, A2AE20, A6QQ77, B6VH75, B6VH76, G3XDT7, O75951, P00697, P00698, P00699, P00700, P00701, P00702, P00703, P00704, P00705, P00706, P00707, P00708, P04421, P08905, P11375, P11376, P11941, P12066, P12067, P12068, P12069, P16973, P17607, P17897, P19849, P22910, P24364, P24533, P30201, P37712, P37713, P49663, P61626

SIGNOR signaling

0 interactions.

Disease & clinical

Clinical variants and AI predictions

ClinVar

1 variants total. Per-class counts are floors (≥ shown; pagination cap):

Classification	Count (floor)
Pathogenic	0
Likely pathogenic	0
Uncertain significance	0
Likely benign	1
Benign	0

Top pathogenic / likely-pathogenic (0)

SpliceAI

231 predictions. Top by Δscore:

Variant	Effect	Δscore
X:48131420:G:GC	donor_loss	1.0000
X:48131420:G:GG	donor_gain	1.0000
X:48131421:T:A	donor_loss	1.0000
X:48132248:A:AG	acceptor_gain	1.0000
X:48132249:G:GG	acceptor_gain	1.0000
X:48132249:GACCT:G	acceptor_gain	1.0000
X:48130814:GGC:G	donor_gain	0.9900
X:48130829:GACT:G	donor_gain	0.9900
X:48130833:G:GG	donor_gain	0.9900
X:48131415:TCATG:T	donor_gain	0.9900
X:48131416:CATG:C	donor_gain	0.9900
X:48131417:ATG:A	donor_gain	0.9900
X:48131418:TG:T	donor_gain	0.9900
X:48131419:GG:G	donor_gain	0.9900
X:48132245:CTCAG:C	acceptor_loss	0.9900
X:48132246:TCA:T	acceptor_loss	0.9900
X:48132247:CAGAC:C	acceptor_loss	0.9900
X:48132248:A:T	acceptor_loss	0.9900
X:48132249:GAC:G	acceptor_gain	0.9900
X:48132324:GCCTG:G	donor_gain	0.9900
X:48132325:CCTGG:C	donor_loss	0.9900
X:48132326:CTGG:C	donor_loss	0.9900
X:48132329:GT:G	donor_loss	0.9900
X:48132330:T:G	donor_loss	0.9900
X:48132249:GA:G	acceptor_gain	0.9800
X:48132329:G:GG	donor_gain	0.9800
X:48132427:TCCCA:T	acceptor_loss	0.9800
X:48132429:CCAGG:C	acceptor_loss	0.9800
X:48132430:CA:C	acceptor_loss	0.9800
X:48132431:A:AG	acceptor_gain	0.9800

AlphaMissense

1059 scored. Top likely-pathogenic:

Variant	Protein change	am_pathogenicity
X:48131345:T:G	F77C	0.990
X:48131368:T:A	C85S	0.990
X:48131369:G:C	C85S	0.990
X:48131401:T:A	C96S	0.989
X:48131402:G:C	C96S	0.989
X:48132433:G:C	W128C	0.989
X:48132433:G:T	W128C	0.989
X:48131266:T:A	C51S	0.988
X:48131267:G:C	C51S	0.988
X:48131357:C:T	S81F	0.988
X:48132452:T:A	C135S	0.988
X:48132453:G:C	C135S	0.988
X:48132478:G:C	W143C	0.988
X:48132478:G:T	W143C	0.988
X:48132285:T:A	C114S	0.986
X:48132286:G:C	C114S	0.986
X:48131345:T:C	F77S	0.985
X:48132442:G:C	W131C	0.985
X:48132442:G:T	W131C	0.985
X:48131262:G:C	W49C	0.983
X:48131262:G:T	W49C	0.983
X:48131356:T:C	S81P	0.982
X:48131339:G:T	G75V	0.980
X:48131342:T:C	I76T	0.979
X:48132454:T:G	C135W	0.979
X:48130832:T:A	W49R	0.977
X:48130832:T:C	W49R	0.977
X:48131290:T:C	F59L	0.977
X:48131292:T:A	F59L	0.977
X:48131292:T:G	F59L	0.977

dbSNP variants (sampled 300 via entrez): RS1158389484 (X:48132676 T>A), RS1158553240 (X:48129808 T>A), RS1159719938 (X:48131731 G>A), RS1160328316 (X:48131044 C>A,T), RS1160476384 (X:48129658 C>T), RS1163797128 (X:48131322 TG>T), RS1163886061 (X:48128886 G>C,T), RS1164106878 (X:48128713 G>C), RS1165269467 (X:48131188 T>C), RS1167283471 (X:48133075 T>C), RS1167961944 (X:48131395 A>T), RS1168094120 (X:48129393 G>A), RS1170774566 (X:48130228 G>C), RS1172997423 (X:48132940 G>A), RS1173134214 (X:48130067 C>T)

Disease associations

OMIM: gene `` | disease phenotypes:

GenCC curated gene-disease

Mondo (0):

Orphanet (0):

HPO phenotypes

0 total (0 of 0 shown, HPO-id order):

GWAS associations

0 associations (top):

Drugs & pharmacology

Drug and pharmacology data

Is drug target: no

PharmGKB: 1 entry (VIP=true, CPIC=false)

Clinical trials (associated diseases)

0 trials via MONDO — disease-level, not drug-specific.