View source for RAB27

{{protein
|Name=[[RAB27A|RAB27A, member RAS oncogene family]]
|caption=
|image=
|width=
|HGNCid=9766
|Symbol=[[RAB27A]]
|AltSymbols=
|EntrezGene=5873
|OMIM=603868
|RefSeq=NM_004580
|UniProt=P51159
|PDB=
|ECnumber=
|Chromosome=15
|Arm=q
|Band=21
|LocusSupplementaryData=
}}
{{protein
|Name=RAB27B, member RAS oncogene family
|caption=
|image=
|width=
|HGNCid=9767
|Symbol=RAB27B
|AltSymbols=
|EntrezGene=5874
|OMIM=603869
|RefSeq=NM_004163
|UniProt=O00194
|PDB=
|ECnumber=
|Chromosome=18
|Arm=q
|Band=21.2
|LocusSupplementaryData=
}}
'''Rab27''' is a member of the [[Rab (G-protein)|Rab]] subfamily of [[GTPase]]s. Rab27 is post translationally modified by the addition of two [[prenylation|geranylgeranyl groups]] on the two C-terminal [[cysteine]]s. 

==Pathology==
Mutations that prevent the expression of Rab27 ('knock out' mutations) cause the hypopigmentation and immunodefficiency disorder known as type II [[Griscelli syndrome]], while a decrease in Rab27 prenylation is thought to be involved in [[choroideremia]]. 

The symptoms of type II [[Griscelli syndrome]] have shown that Rab27 is involved in [[melanosome]] transport in [[melanocytes]] and in cytotoxic killing activity in cytotoxic T [[lymphoblasts]]. In melanocytes Rab27 binds the melanosome. The melanosome is transported along the [[microtubule]]. Rab27 then recruits [[Slac2A]] and [[myosin]] Va, these enzymes are essential for the transfer of the melanosomes from the microtubules to [[actin]] filaments. The melanosomes can now continue on their path towards the cell periphery. If either Rab27, Slac2A or myosin Va are absent then the melansomes remain in the perinuclear region of the cell. This disruption in pigmentation results in the hypopigmentation seen in the silvery hair colour of patients with [[Griscelli syndrome]]. 

==External links==
* {{MeshName|RAB27A+protein,+human}}
* {{MeshName|RAB27B+protein,+human}}

[[Category:Signal transduction]]
[[Category:EC 3.6.5]]

{{biochemistry-stub}}
{{Acid anhydride hydrolases}}
{{Enzymes}}
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