Dataset Information

Calpain activity is regulated by a KCTD7–cullin 3 complex via non-degradative ubiquitination

ABSTRACT: Calpains are a class of non-lysosomal cysteine proteases that exert their regulatory functions via limited proteolysis of their substrates. Similar to the lysosomal and proteasomal systems, calpain dysregulation is implicated in the pathogenesis of neurodegenerative disease and cancer. Despite intensive efforts placed on the identification of mechanisms that regulate calpains, however, global regulators of calpains activity have remained elusive. Here we show that calpains are regulated by KCTD7, a cytosolic protein of previously uncharacterized function whose pathogenic mutations result in epilepsy, progressive ataxia, and severe neurocognitive deterioration. We show that KCTD7 works in complex with Cullin-3 and Rbx1 to execute atypical, non-degradative ubiquitination of calpains at specific sites (K398 of calpain 1, and K280 and K674 of calpain 2). Experiments based on single-lysine mutants of ubiquitin determined that KCTD7 mediates ubiquitination of calpain 1 via K6-, K27-, K29-, and K63-linked chains, whereas it uses K6- mediated ubiquitination to modify calpain 2. Loss of KCTD7-mediated ubiquitination of calpains led to calpain hyperactivation, aberrant cleavage of downstream targets, and caspase-3 activation. CRISPR/Cas9-mediated knockout of Kctd7 in mice phenotypically recapitulated human KCTD7 deficiency and resulted in calpain hyperactivation, behavioral impairments, and neurodegeneration. These phenotypes were largely prevented by pharmacological inhibition of calpains, thus demonstrating a major role of calpain dysregulation in KCTD7-associated disease. Finally, we determined that Cullin-3–KCTD7 mediates ubiquitination of all ubiquitous calpains. These results unveil a global mechanism and potential target to restrain calpain activity in human disease and shed light on the molecular pathogenesis of KCTD7-associated disease.

INSTRUMENT(S): Bruker Daltonics timsTOF series

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: Byoung-Kyu Cho

LAB HEAD: Young Ah Goo

PROVIDER: PXD038842 | Pride | 2023-05-10

REPOSITORIES: Pride

ACCESS DATA

Dataset's files

Source:

			Action	DRS
	20220503_bkc_22-0020_Sardiello_Sharma_01-FLAG_Slot1-10_1_8311.d.zip	Other
	20220503_bkc_22-0020_Sardiello_Sharma_02-KCTD7_Slot1-11_1_8314.d.zip	Other
	20220503_bkc_22-0020_Sardiello_Sharma_03-FLAG_Slot1-12_1_8312.d.zip	Other
	20220503_bkc_22-0020_Sardiello_Sharma_04-KCTD7_Slot1-13_1_8315.d.zip	Other
	proteinGroups.txt	Txt

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Publications

Calpain activity is negatively regulated by a KCTD7-Cullin-3 complex via non-degradative ubiquitination.

Sharma Jaiprakash J Mulherkar Shalaka S Chen Uan-I UI Xiong Yan Y Bajaj Lakshya L Cho Byoung-Kyu BK Goo Young Ah YA Leung Hon-Chiu Eastwood HE Tolias Kimberley F KF Sardiello Marco M

Cell discovery 20230324 1

Calpains are a class of non-lysosomal cysteine proteases that exert their regulatory functions via limited proteolysis of their substrates. Similar to the lysosomal and proteasomal systems, calpain dysregulation is implicated in the pathogenesis of neurodegenerative disease and cancer. Despite intensive efforts placed on the identification of mechanisms that regulate calpains, however, calpain protein modifications that regulate calpain activity are incompletely understood. Here we show that cal ...[more]

PMID: 36964131

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