KLHL12

This gene encodes a member of the KLHL (Kelch-like) family of proteins. This protein has been identified as an autoantigen in the autoimmune disease Sjogren's syndrome and as a potential biomarker in primary biliary cirrhosis. This protein may act as a substrate adaptor of the Cullin-3 ubiquitin ligase complex to promote substrate-specific ubiquitylation. Ubiquitylation by this complex has been shown to regulate the Wnt signaling pathway as well as COPII vesicle coat size. A pseudogene has been identified on chromosome 22. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2014]

Full Name

Kelch Like Family Member 12

Function

Substrate-specific adapter of a BCR (BTB-CUL3-RBX1) E3 ubiquitin ligase complex that acts as a negative regulator of Wnt signaling pathway and ER-Golgi transport (PubMed:22358839, PubMed:27565346).
The BCR(KLHL12) complex is involved in ER-Golgi transport by regulating the size of COPII coats, thereby playing a key role in collagen export, which is required for embryonic stem (ES) cells division: BCR(KLHL12) acts by mediating monoubiquitination of SEC31 (SEC31A or SEC31B) (PubMed:22358839, PubMed:27565346).
The BCR(KLHL12) complex is also involved in neural crest specification: in response to cytosolic calcium increase, interacts with the heterodimer formed with PEF1 and PDCD6/ALG-2, leading to bridge together the BCR(KLHL12) complex and SEC31 (SEC31A or SEC31B), promoting monoubiquitination of SEC31 and subsequent collagen export (PubMed:27716508).
As part of the BCR(KLHL12) complex, also acts as a negative regulator of the Wnt signaling pathway by mediating ubiquitination and subsequent proteolysis of DVL3 (PubMed:16547521).
The BCR(KLHL12) complex also mediates polyubiquitination of DRD4 and PEF1, without leading to degradation of these proteins (PubMed:18303015, PubMed:20100572, PubMed:27716508).

Biological Process

COPII vesicle coatingManual Assertion Based On ExperimentIMP:UniProtKB
Endoplasmic reticulum to Golgi vesicle-mediated transportManual Assertion Based On ExperimentIDA:UniProtKB
Neural crest cell developmentManual Assertion Based On ExperimentIMP:UniProtKB
Neural crest formationManual Assertion Based On ExperimentIMP:UniProtKB
Protein monoubiquitinationManual Assertion Based On ExperimentIDA:UniProtKB
Wnt signaling pathwayManual Assertion Based On ExperimentIMP:UniProtKB

Cellular Location

Cytoplasmic vesicle, COPII-coated vesicle

PTM

Ubiquitinated by the SCF(FBXL17) complex, leading to its degradation by the proteaseome: ubiquitination by the SCF(FBXL17) complex takes place when aberrant BTB domain dimers are formed.